Statcast Pitcher Studs and Duds - Advanced Metrics Leaders for ERA-xERA (Week 20)

Welcome back to another edition of RotoBaller’s Statcast Pitcher Studs and Duds article series! Each week, I select one advanced metric, choose two pitchers with strong values and two with poor values, and analyze what those values may mean for future performance.

With fantasy trade deadlines quickly approaching, comparing peripheral numbers to expected metrics is a great method for identifying buy-low and sell-high candidates. This week, I will be comparing pitchers' ERA to their expected ERA (xERA). This comparison can generally be used to find pitchers who have gotten lucky or unlucky based on their underlying performance.

Fantasy managers have difficult roster decisions to make at this point in the season and may still have time to make some final trades. Understanding how starters have pitched in comparison to their results can play a role in informing these decisions. With that in mind, let's identify some ERA-xERA Studs and Duds!

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ERA-xERA Studs for Fantasy Baseball

All stats are current as of Sunday morning, August 6, 2023.

Pablo Lopez, Minnesota Twins

6-6, 4.01 ERA, 3.22 xERA, 0.79 ERA-xERA

Pablo Lopez has continued to improve in his first season with the Twins, compiling a 4.01 ERA, 1.12 WHIP, and 29.9% strikeout rate in 22 starts. Even more encouraging, his 3.22 xERA suggests that he has almost one run of potential regression to go. Should fantasy managers expect this from him?

Positive regression is something that has been expected of Lopez all season based on his Statcast profile. He has done a solid job limiting hard contact while inducing both swings and misses as well as called strikes. Consequently, all of his expected stats are above average, not just his xERA.

Lopez should hopefully continue to regress to his expected results if he continues to rely on his new sweeper. He has introduced the pitch fully this season, throwing it 20.9% of the time. It has been arguably his best pitch, with a .175 batting average, a .388 slugging percentage, and a 14.8% swinging-strike rate.

All signs point to Lopez pitching a good deal better than his current ERA, which hasn't even been awful. His new pitch mix has helped ramp up strikeouts, he has a great batted-ball profile, and he has an above-average defense behind him. I would want Lopez in my fantasy rotation down the stretch and believe in his xERA.

Yu Darvish, San Diego Padres

8-7, 4.41 ERA, 3.67 xERA, 0.74 ERA-xERA

Yu Darvish's fantasy upside is well known, but so is his tendency to produce inconsistent results. He is currently in the midst of a down season, compiling an 8-7 record with a 4.41 ERA, 1.25 WHIP, and 25.4% strikeout rate. On the positive side, his 3.67 xERA is much lower than his current ERA. Are there enough signs to suggest that positive regression can occur for him this season?

One of the most difficult aspects of evaluating Darvish is his ever-changing pitch mix. The veteran has effectively thrown seven different pitches this season, with his pitch mix varying considerably by month. With so many pitches thrown with such different frequencies, it is hard to identify any true patterns.

One thing that is identifiable is Darvish's first-half vs. second-half numbers. He compiled a poor 4.87 ERA, 1.27 WHIP, and .309 BABIP through 85 innings pitched. Through his 29 1/3 second-half innings, he has a solid 3.07 ERA, 1.19 WHIP, and .270 BABIP.

Unfortunately, a closer look only brings up more questions. While his second-half BABIP is lower, Darvish has allowed more hard contact at 39.2% compared to 32.5% in the first half. He has also allowed more fly balls and a higher HR/FB rate in the second half despite the better ERA.

Darvish is a jumbled bag of analyses thanks to a refusal to throw a limited pitch mix. His numbers have fluctuated both month by month and between halves of the season, but there are few trends to feel comfortable about. Darvish has pitched better in the second half, but his underlying numbers don't necessarily support the improvement.

His xERA may be lower than his current ERA, but it is difficult to find any additional supporting signs. Overall, I think fantasy managers can only hold onto Darvish and hope that he can continue to find success down the stretch despite the mixed underlying signals.

ERA-xERA Duds for Fantasy Baseball

All stats are current as of Sunday morning, August 6, 2023.

J.P. France, Houston Astros

7-3, 2.85 ERA, 4.41 xERA, -1.56 ERA-xERA

J.P. France has not stood out as an exciting fantasy option this season but has been a consistent contributor, going 7-3 with a 2.85 ERA, 1.22 WHIP, and 17% strikeout rate through 15 starts. His peripherals are good overall, but his 4.41 xERA is over a run-and-a-half higher than his ERA. Is this the type of player fantasy managers should trust down the stretch?

Part of the explanation behind France's higher xERA is his lack of strikeouts. France does not have overpowering stuff and pitches to contact at a clip of 79.3%. His batted-ball profile is above-average, with an exit velocity and hard-hit rate in the 59th and 70th percentiles of baseball, respectively, to go with an 11.4-degree launch angle. However, his 4.78 SIERA suggests that his batted-ball profile still leaves something to be desired.

On the plus side, France makes up in quantity what he may not have in upside. 10 of his 15 starts have been quality starts, including five seven-inning efforts. This may limit his fantasy value in roto leagues, but it doesn't matter as much in points leagues where innings lead to more points.

Don’t ever underestimate The Stache!

J.P. France has completed seven innings for the third time in a row!

Another quality start! pic.twitter.com/NT6Da8SzhB

— Full Seam Ahead (@FullSeamAhead) August 1, 2023

I don't think fantasy managers are taking France's overall numbers at face value, which makes sense. However, it is not uncommon for players to outperform their underlying metrics, particularly if they bring a sound approach to the game. France isn't the best pitch-to-contact pitcher, but he has done a decent job avoiding hard contact and has pitched deep into games.

I would certainly not be surprised to see France experience some regression down the stretch, but I'm not sure that fantasy managers could get a great return if they tried to sell high because of his low strikeout numbers. Even if regression does occur, I still think France is a worthwhile arm to have, particularly in points leagues.

Alex Cobb, San Francisco Giants

6-3, 3.05 ERA, 4.44 xERA, -1.39 ERA-xERA

Alex Cobb has been a useful fantasy starter for several seasons now and has a 3.05 ERA, 1.32 WHIP, and 21.9% strikeout rate through 20 starts. One ominous sign is his 4.44 xERA, which has almost as poor of a difference from his ERA as France's. Is this something fantasy managers need to worry about?

Like France, Cobb is a pitch-to-contact pitcher with an 80.1% contact rate. Unlike France, Cobb is and has been an elite groundball pitcher. He has allowed pretty hard contact this season but has limited damaging contact due to a career-low 0.8-degree launch angle.

Cobb's xERA is not great, but his 3.34 xFIP and 3.67 SIERA suggest that his batted-ball profile should lead to success despite the hard contact. His .330 BABIP is higher than his .300 career mark, which may have to do with shift limitations this season. Regardless, he has gotten good results while relying on a tried-and-true pitching approach.

Cobb instills more confidence than France because he has shown proven success with his current approach, despite what his xERA says. Cobb won't strike out a lot of hitters and will give up hard contact, but this should lead to positive results because he does such a good job keeping the ball on the ground. Again, he may not be the most exciting fantasy option, but his consistent production should help keep managers in matchups the rest of the way.

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