As I wrote earlier today, the Baltimore Orioles compensate for a shaky starting rotation with a lights out bullpen. Now comes the news of a trade that sends relief pitcher Matt Lindstrom to Arizona for starting pitcher Joe Saunders. The addition of Saunders will likely bounce 24-year-old lefty Zach Britton out of the rotation. Britton’s 3-1 record belies his 5.59 ERA. However, a look at the advanced metrics suggests that Saunders is not much of an improvement over Britton.
- SIERA– Skill Interactive ERA is not that confusing. According to Fangraphs, “SIERA attempts to answer the question: what is the underlying skill level of this pitcher?” SIERA accounts for many factors that attempt to even the playing field for all pitchers and only punish them for their own mistakes. Joe Saunders currently owns a 4.21 SIERA while pitching in the National League West. The man he was traded for, Lindstrom, owns a 3.51 SIERA. The man Saunders will likely bump in the rotation, Britton, has a 4.49 SIERA. It is interesting that Saunders’ ERA is 4.22, which makes sense considering that Arizona is about a league average fielding team. Baltimore is the second worst fielding team in baseball, which helps explain Brittons 1.10 point increase in his real ERA compared to his SIERA. Expect Saunders’ ERA to increase with Baltimore for two reasons: one, he will face better lineups and two, his fielders are now worse.
Baltimore tapped their strongest resource, bullpen pitching, to improve their weakest asset, starting pitching. However, Saunders career win-loss record is heavily inflated due to solid defense. His lifetime ERA of 4.17 is lower than his lifetime SIERA of 4.66. His career season of 2008, when he went 17-7, is significantly attributable to solid defense as his ERA that year was 3.41 but his SIERA was 4.71. Saunders is a slight upgrade over Britton, but the loss of Lindstrom, and his solid 3.51 SIERA, may prove to be the biggest impact of this trade.
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