Despite his mechanical changes and surface-level success with the Rays since August 26th, many of Freddy Peralta’s underlying stats remain quite similar to his bad stretch with the Mets.

[u/Swimming-Reindeer-39]

Disclaimer: No this is not coming from a salty Mets fan despite my flair. I am happy that Freddy is having success, but there are extremely important caveats to that success. 

Ever since August 26th, it may seem like Freddy Peralta is one of the best pitchers in baseball if you just look at ERA. However, for all that has been made about Peralta’s latest string of success, it is noteworthy how many of his underlying peripherals have gone effectively unchanged.

Comparing ERA, FIP, xFIP, and SIERA
Freddy Peralta 3/26 to 8/25: 5.33 ERA / 4.66 FIP / 4.36 xFIP / 4.34 SIERA
Freddy Peralta 8/26 to 9/25: 0.79 ERA / 2.78 FIP / 4.44 xFIP / 4.27 SIERA
Freddy Peralta’s Postseason: 0.84 ERA / 3.76 FIP / 4.94 xFIP / 4.43 SIERA

Despite far lower ERAs through the last two periods, Peralta’s FIP doesn’t change as much and his xFIP and SIERA remain virtually identical across all three periods. That is notable, since xFIP and SIERA are stats that claim to account for elements “within pitcher control” that ERA can’t fully capture. If xFIP and SIERA say that Peralta has been the same pitcher for basically the entire year, what is causing them to disagree with ERA so much?

xFIP and SIERA usually try to account for Left on Base %, BABIP against, and Home Run to Fly Ball rate. SIERA more actively tries to take batted ball distribution into account, while xFIP just normalizes HR/FB rate within the normal FIP stat. These peripheral stats try to account for things that may be considered “luck-based” for a pitcher. And when examining these peripheral stats for Peralta, they certainly paint a picture of a pitcher who was getting extraordinarily unlucky before now getting extraordinarily lucky. 

More peripheral stats (for outcomes the pitcher doesn’t typically control themselves):
Freddy Peralta 3/26 to 8/25: 67.0% LOB / .311 BABIP / 13.6% HR/FB
Freddy Peralta 8/26 to 9/25: 94.0% LOB / .187 BABIP / 2.2% HR/FB
Freddy Peralta’s Postseason: 100.0% LOB / .207 BABIP / 5.9% HR/FB

Freddy Peralta’s strand rate (LOB%) after August 26th is absurdly high, and is way higher than any qualified pitcher in that timespan by a long shot when the league-average is 72.3%. It isn't uncommon to see ace pitchers maintain high strand rates in a season, but it is still luck-based enough to the extent that fluctuations in small samples can heavily affect ERA.

Maintaining low BABIPs is more controllable, but it is rare for it to hover around or below .200 over a larger sample. It is also more suspect with Peralta given that he has never been much of a groundball pitcher, but improved stuff can definitely still help with this if it decreases hard hit rate. This is also why xERA (which isn't listed here) has improved given worse quality of contact against, even if the batted ball distributions that go into SIERA doubt that it can sustain itself. Improved defense can also help with lower BABIPs.

HR/FB rate usually hovers around 11%, and it is generally not expected for a pitcher to maintain rates that are wildly below or above that mark for an extended period of time. However, small samples can produce low HR/FB rates that paints a more rosy picture of a pitcher’s ability.

tl;dr: Even if Freddy Peralta has improved as a pitcher on the Rays compared to the Mets, that improvement is being heavily obfuscated by stats that indicate that he is getting highly lucky across this specific sample of starts. As a matter of fact, certain peripheral stats don’t actually believe he is a very different pitcher at all. His true pitching ability is somewhere in between his Mets self and his Rays self.

[u/mtportales]

He went from a team with -22 OAA to one with 6 OAA. The Mets specifically had -6 FRV when he was on the mound. The rays have given him +7 FRV in significantly fewer innings pitched. That explains a significant amount of the difference in performance.

Peralta was a poor fit on the Mets and is a perfect match for the rays.

[u/eb12se4nt-z13ow-97g0 → u/mtportales]

Freddy also started awful with us in his first few starts, our defense was the same so he definitely changed something up with our pitching staff.

[u/OrganicValley_ → u/eb12se4nt-z13ow-97g0]

I’m pretty sure his change up usage went up like 30% with the Rays

[u/bordomsdeadly → u/OrganicValley_]

Got change up how many change ups you throw sometimes

[u/StevenMC19 → u/OrganicValley_]

I was also told that the coaches had him reposition himself on the mound further over to the side of the rubber. And apparently his angle of attack has sharpened a bit.

[u/dusters → u/OrganicValley_]

FB velocity is also up

[u/Wooden-Repeat-9200 → u/mtportales]

Defense- and particularly defensive positioning- is highly underrated.

[u/Spinnie_boi → u/mtportales]

That his FIP is better but his xFIP and SIERA aren’t tells you everything you need to know. He’s happened to not give up homers over an admittedly short stretch. Any Cubs fan can tell you that defense can’t prevent homers, and over smaller samples, defense won’t make the same difference that fluctuations in BABIP and HR/FB will, which is exactly what’s happening here

[u/perezh → u/mtportales]

I'd like to see his ball/strike numbers and mechanical efficiency more. His pirch mix definitely changed on the rays. But every smart team knew Freddy was in for regression on his numbers, including the Mets. 67% lob is not sustainable. That's why his return was better than expected for his surface level stats.

[u/danger-cat → u/mtportales]

David Petersen’s results also got better when he went from the Mets to the Cubs despite his FIP staying pretty similar. Perhaps the Mets defense just really is that bad.

[u/bowlofcantaloupe → u/danger-cat]

The beginning of the season we had Lindor injured and Bichette taking over at SS. Plus an injured and old Marcus Semien who would eventually go on IL and stop playing every game when he returned.

[u/grandmoffpoobah → u/[deleted]]

Because FIP doesn't care about defense

[u/RedRockRiviera → u/grandmoffpoobah]

Yes, that is my point.

[u/grandmoffpoobah → u/RedRockRiviera]

But like what point is being made by saying that something that doesn't influence something still doesn't influence it?

[u/AccomplishedDust3 → u/[deleted]]

FIP and xFIP (try to) measure pitching in an imaginary world where defense is the same for everyone.

ERA doesn't control for anything, so it includes pitching performance, fielding, and luck. Good defense should improve the ERA of everyone on a team relative to if they were in a team with poor or average defense.

If you go from having poor defense to having good defence, you would expect FIP and xFIP to stay the same but ERA to improve: the pitcher is the same, the fielding is different, so a fielding-dependent stat like ERA changes, where a fielding-independent stat like FIP does not.

Of course luck and small sample sizes can mess with all of this.

[u/cabose7]

Throwing upper 90s since he joined the Rays probably has helped the results

[u/RedRockRiviera → u/cabose7]

iirc his average velo has only changed by ~1 MPH

[u/cabose7 → u/RedRockRiviera]

In last night's outing he threw the hardest pitch of his career and had an avg velocity of 96.9 - up from 94.3 in the regular season. He also threw 27 pitches above 97 mph, the most in his career for one game.

[u/brett_baty_is_him → u/cabose7]

It’s pretty common for velo to jump in playoffs. I would treat that as a statistical outlier with an obvious explanation

[u/RedRockRiviera → u/cabose7]

ok yea he’s dealing

[u/foomits → u/cabose7]

this is what i dont understand about this post. not that im disagreeing with the assessment, but legitemately dont understand.

he comes in and we change what pitches he throws and when. he is now pitching only out of the stretch, hes getting longer extension on his plant food and hes throwing harder...

how do we get a completely new outcome and say, well not of that is actually meaningful? or am i just totally not getting it.

[u/Cgmulch → u/foomits]

You're not getting it

[u/LavarBallsLeftNut → u/RedRockRiviera]

Brewers pitching staff has unlocked 6-8 more inches of extension to Freddy P’s release point. That diff makes his 94-96 mph fastball look like it’s coming in at 98-100mph now.

[u/evancomposer]

Rays have good defense, the Mets do not.

[u/floyd_mongol]

this is some hardcore cope. why cant you just accept the fact that the rays are a well run organization and the mets are not.

[u/imatthewhitecastle → u/floyd_mongol]

We should just not have team flairs. This post is an interesting observation and it is interesting to neutral fans that his predictive numbers haven’t changed. It shows that the Rays are doing something different with him that isn’t captured by those stats, and I would think that any fan would be curious as to what that is. Yet even with the disclaimer, OP just gets responses like this from people who look at the flair and make assumptions. There isn’t a bitter word in OP’s entire post.

[u/foomits → u/imatthewhitecastle]

I'm not smart enough to full understand all the stats.

But (and this has sort of been mentioned ad nauseum), beyond changing his pitch mix, he also is now working out of the stretch and getting 3 inches further extension on his plant foot.

I appreciate there are people who understand these metrics way better than me. but can someone explain so I can understand why a player could make significant changes to their approach, leading to improved outcomes but the underlying metrics would say well.. actually those things didnt matter?

[u/futhatsy → u/foomits]

I think it's 2 things:

1. Stats like xFIP and SIERA are not perfect. SIERA in particular is pretty rarely used these days. xFIP treats all balls in play the same and assumes a normal HR/FB rate. I think it's likely that Peralta made tangible changes for the better that just are not being picked up by these stats.

2. Even if we accept that the mechanical and pitch mix adjustments helped Peralta turn his season around, it's probably not 100% of the reason his ERA went from over 5.00 to under 1.00. Some of this is a regression to the mean in batted ball and sequencing luck.

When some stats say it's all a change in luck, and other stats point to clear improvements, it's probably a combination of the two.

[u/pepperouchau → u/imatthewhitecastle]

He’s significantly changed his pitch mix with the Rays as was mentioned on the tv broadcast

[u/takethreenc → u/imatthewhitecastle]

It's cope let's be for real now.

[u/RedRockRiviera → u/floyd_mongol]

What a dumb comment. Did you even read the post?

[u/atoms12123 → u/RedRockRiviera]

Some Mets fans only exist to complain about the team, no matter what.

[u/yumyumapollo]

After adjusting Patrick Mahomes' stats, removing outliers to project the future, he heavily regresses to around the level of 2018 Dak.

[u/timeisnownotomorrow]

Peralta’s mechanical adjustments completely transformed his real-world results. By abandoning his lowered, sluggish Mets arm slot for a much more vertical delivery and shifting to the extreme third-base side of the rubber, he completely altered his pitch movement. Because traditional stats like FIP, xFIP, and SIERRA rely strictly on rigid league averages, they are completely incapable of accurately measuring Peralta’s actual elite performance since his mechanical changes. Using season-long spreadsheet averages to judge a pitching overhaul is just lazy analysis that fails to account for the reasons for his improved performance.

Back with the Mets (5++ ERA,), he had a flawed delivery with no deception or exrensiony, a flat fastball with no movement, and absolutely no command of his pitches. Since his August 26 transformation with the Rays, he completely upgraded his profile and broke the formulas by using:

• Elite Deception: His new vertical slot combined with a 7-foot extension and angled delivery gives his four-seamer explosive, un-squarable late "rise" at the top of the zone. His fastball's velocity now appears even faster to batters as they have less time to react.

• Tunnelling: He switched to a heavy fastball/changeup mix. Out of his more vertical arm slot pitches now look identical for the first 24 feet before the changeup dives, destroying a hitter's timing.

• Statcast Validation: His xERA-the most accurate stat for measuring a pitcher who is consistently throwing a batters timing off- is 2.12 over those 6 regular-season games, and is at a dominant 2.35 in the postseason. His quality of contact metrics rate in the 95% percentile or above across the board. His opponent hard-hit rate plummeted from 41.3% to 26.8%, with a weak 83.4 MPH average exit velocity.

Go watch the actual tape. He completely choked out the Yankees in the ALDS sweep, then jammed the Guardians in ALCS Game 2 by throwing his fastball 71.7% of the time and registering a carear high 99.4 mph and a game average of 96.9 mph. He locked down Lowe up and in, left Quan totally mistiming balls, and blew a changeup right past Halpin.

Metrics like xFIP and SIERRA just see fly balls and lazily assume luck. Statcast's xERA proves his sub-0.85 ERA is real because his new vertical mechanics induce weak pop-ups. He didn't get lucky; he evolved.

[u/NlNJALONG]

Yeah this is definitely coming from a content Mets fan who's definitely happy for his close friend Freddy that he's doing so well for his new team.

[u/akaghi → u/NlNJALONG]

Mets got a pretty solid return for what was essentially the worst pitcher in baseball at the time.

[u/NuanceManExe → u/akaghi]

If Peralta had pitched like Peralta during the first half we would’ve gotten a better return than we got for Holmes, which was an actual great return. It’s also the Rays. They rarely trade the wrong guys. The best trades with the Rays are the cost cutting ones where they’re getting rid of a player just to save money, like Raley, so there’s less opportunity for them to fleece you.

[u/hangout_wangout → u/NlNJALONG]

I'm a freddy p fan and im stoked for him being in the postseason and doing well.

[u/llOneXll]

I'm just unsure why the Mets insisted on him pitching from the stretch

[u/TheRegurgitat0r → u/llOneXll]

He’s exclusively pitched from the stretch with the Rays is that what you mean? He pitched from the windup with the Mets.

[u/Clipbored_ → u/TheRegurgitat0r]

He actually started the year pitching from the stretch and only tried pitching from the windup when it wasn't working for him. It was the start against the Cubs in June if I remember correctly.

[u/llOneXll → u/TheRegurgitat0r]

That's correct. Thank you

[u/vaporgaze2006 → u/llOneXll]

They mentioned that on the broadcast last night.

[u/llOneXll → u/vaporgaze2006]

Oh mb. I usually watch with the audio low. I guess its obvious in retrospect

[u/mysterysackerfice → u/[deleted]]

I know for a fact that last month he said "And now for my next trick, I will strand 94% of baserunners....TADA!"

[u/Onitsukaryu → u/[deleted]]

^bot regurgitating text from the post.