Stat of the Week: Who Were The Top Overachieving & Underachieving Pitchers in 2018

Who Were the Overachieving & Underachieving Pitchers in 2018?

March 26, 2019

By Mark Simon

Who were the overachievers and underachievers of the 2018 MLB season?

It’s a question to consider for those evaluating their teams and conducting their fantasy drafts as the season begins. Though there are no guarantees that the numbers will even out and that the player will return to his expected norms, understanding who overachieved and underachieved provides context to a player’s past performance.

Last week's Stat of the Week looked at this for hitters. This week, the focus is on pitchers.

Our Defense-Independent Pitching Statistics (DIPS) can give expected results on every ball in play for a pitcher by comparing the ball's trajectory, direction and velocity to other similar batted balls and assigning value based on those results. We can then compare those to his actual numbers to determine if a player underachieved or overachieved.

In other words, these numbers can tell us if a player may have pitched in hard luck, worked in an unfriendly ballpark, or been the victim of some poor defense. Or perhaps he pitched with good luck, got a few ballpark-friendly outs, or took advantage of some good defense.

Here's a look at some notable pitchers in both categories heading into 2018, along with their projections for 2019.

Underachievers

Marco Estrada has deserved better than he’s gotten the last two seasons. This is his second straight season on the underachiever list.

In 2018, Estrada’s BABIP allowed was 40 points above expectations. His OPS allowed was 98 points above expectations, the highest above for any starting pitcher who faced at least 300 batters last season. Estrada's BABIP allowed was a sharp contrast from 2015 and 2016 when Estrada posted back-to-back seasons with BABIPs of .217 and .234 with the Blue Jays.

Estrada is going from the AL’s worst team in Defensive Runs Saved (Blue Jays) in 2018 to the best (Athletics), which may help him achieve his projected numbers more easily.

Estrada’s 2019 projection: 4.26 ERA, 11.9 baserunners per 9 in 146 IP

The Phillies had three names among the five biggest differentials.

Zach Eflin, Vince Velasquez and Nick Pivetta may have been worthy of a better fate. Each of the three had an expected OPS allowed at least 75 points better than his actual OPS allowed (the lowest ERA was Eflin's 4.36). Pivetta got the spotlight in this space a year ago as well.

The Phillies defense has not been kind to its pitchers the last couple of seasons. The team set a record last year for worst Defensive Runs Saved total. This year’s team is expected to contend for NL East supremacy and it should be interesting to see if the defense rises to the occasion and provides support to these pitchers.

Eflin 2019 projection: 4.19 ERA, 12.3 baserunners per 9 in 141 IP

Velasquez 2019 projection: 4.10 ERA, 12.7 baserunners per 9 in 144 IP

Pivetta 2019 projection: 3.96 ERA, 12.3 baserunners per 9 in 166 IP

Overachievers

Michael Wacha missed half the season due to injury, but in the time in which he pitched, he was very good. As noted in an article for The Athletic last season, Wacha got significant help from the Cardinals’ defense.

Wacha allowed a .646 OPS, despite his expected OPS allowed being .837. The 191-point differential was the most a pitcher’s OPS allowed was below expectations among those who faced at least 300 batters in 2018.

If Wacha had allowed an .837 OPS last season, he would have been challenged to post his 3.20 ERA. Among pitchers with at least 90 innings pitched and an .800 OPS allowed, the lowest ERA was Padres pitcher Eric Lauer’s 4.34.

Wacha is projected for a drop-off in 2019.

Wacha 2019 projection: 4.16 ERA, 12.6 baserunners per 9 in 118 IP

Brewers pitcher Jhoulys Chacin also had good defense on his side. The Brewers finished second in the majors in Defensive Run Saved, trailing only the Diamondbacks. Chacin’s opponents’ batting average on both ground balls and line drives ranked among the lowest 15 percent in MLB. That helped him hold opponents to a .655 OPS, 156 points below expectations. It will be a challenge to maintain that and his 2018 ERA of 3.50 this season.

Chacin 2019 projection: 4.05 ERA, 12.0 baserunners per 9 in 193 IP

Another pitcher who benefited from his team's defense was Braves starter Julio Teheran. Teheran allowed only 6.3 hits per 9 innings, though our model showed he allowed 27 hits fewer than expected based on where and how hard balls were hit against him. Teheran was nearly the same pitcher in 2018 as he was in 2017, with regard to his strikeouts, walks, and home runs allowed. But the work by those behind him proved helpful to his numbers. He's projected for similar stats in 2019.

Teheran 2019 projection: 4.07 ERA, 11.7 baserunners per 9 in 178 IP.

A reminder that you can purchase the updated 2019 Bill James Player Projections at this link.