Final Pitcher ERA-SIERA Differential: The Potentially Undervalued

On Saturday, I took a look at the five pitchers whose ERAs were the most below their SIERA marks, which suggests that they may be overvalued in next year’s drafts. Today I will look at the opposite, the five pitchers whose ERAs were the most above their SIERA marks, which might lead to them being undervalued in drafts next season.

Brandon Morrow

There has been enough written, debated and speculated about Morrow’s two seasons in a row of significant SIERA underperformance. This year, it was mainly a low LOB% that inflated his ERA, while last year it was primarily a ridiculous BABIP. That’s a good thing, because at least we know it isn’t one metric he consistently posts lower than league average marks in, which would make us question if he just lacks that particular skill. Interestingly, his career BABIP is at exactly .300, HR/FB ratio just below league average at 9.2%, and LOB% a reasonable 70.8%. Yet, his career ERA is an underwhelming 4.37, compared to a more impressive 3.66 SIERA. xFIP likes him less though, as its 3.94 career mark tells us, and is likely the result of SIERA treating extreme fly ball pitchers better than xFIP. For a pitcher with his strikeout ability, his expected LOB% should probably be higher, so maybe he really does have slightly lesser skills in that department. However, he has only made basically the equivalent of two season’s worth of starts, so I think it is still too soon to know for sure if that is the case. His perceived value has likely hit bottom, so there’s no excuse not to take a shot again next year.

Derek Lowe

With reports of Lowe not opening next season in the Braves rotation, the team might want to remember what happened with Kelly Johnson not too long ago. The team chose not to resign Johnson after a disappointing 2009 season. But all they had to do was look at his .247 BABIP and realize it was just bad luck and he should rebound. And rebound he sure did in 2010. On the surface, Lowe looks done as a reliable starting pitcher, but his skills and expected ERA metrics have been as consistent as it gets (with the exception of 2009). Lowe has gone through patches with inflated BABIPs before and as an extreme ground ball pitcher, the defense behind him plays a huge role in his ultimate performance. I think the Braves would be foolish to just give up on him and fantasy owners, especially NL-Only ones, would be smart to take a cheap gamble no matter what his role is to open the year.

A.J. Burnett

Hmmm, his skills look very similar to the vintage Burnett we used to be accustomed to when he was posting ERAs below 4.00 each year. What really killed him was a crazy 17% HR/FB ratio, a level he has actually experienced once before back in 2007. The next year, his HR/FB ratio dropped right back down to a more normal 9.6%. Last season, Burnett’s skills were legitimately diminished, and though he did not deserve an ERA above 5.00, it was not a very good year. Now after posting an ERA above 5.00 for a second straight year, his perceived value is likely at an all-time low. Although I am somewhat concerned about his declining fastball velocity, he could yield a nice profit at little cost in drafts next year.

Zack Greinke

Aside from the awful Brewers defense hurting Greinke’s BABIP, he has had a history of posting above league average marks. In fact, he has not posted a mark below .303 since his rookie year in 2004. That may very well be a result of perennially poor Royals defense, or some lack of skill in this department or a combination of both. Besides the high BABIP, a 13.6% HR/FB ratio was problematic, but luckily he does not have a history of high marks here and his career rate is still just 9.0%. He led all MLB pitchers in SIERA, so he could be one of the few pitchers drafted as a team’s ace that actually yields a big profit.

Fausto Carmona

He pitched very similarly to last season, yet his ERA jumped from 3.77 to 5.25. He was absolutely lucky last year, but certainly did not deserve to suffer through regression to this degree. His poor strikeout rate will limit his fantasy value and he has had trouble stranding base runners in the past. With his extreme ground ball ability and a return to solid control, he should never see an ERA above 5.00 again. However, only AL-Only leaguers will really want to roll the dice as his upside just isn’t high enough to be worth gambling on in mixed leagues.