How Much Worse Should Shane Bieber's ERA Really Be?
Shane Bieber takes a 4.99 ERA into this afternoon's start at Tropicana Field, and against a Tampa Bay team running away with the best record in the sport, that already reads like the tougher assignment. Baseball Savant's version of his season says the number is being generous.
Bieber's xERA sits at 6.85 — 1.86 runs worse than his actual mark, one of the widest overperformance gaps of any starter this season. Opponents are barreling him up at an 11.5% clip and hitting him hard 47.4% of the time, both numbers that look nothing like a pitcher who's merely had a bumpy year. Whatever has kept the actual damage a run and a half below what the contact quality says it should be — sequencing, a defense doing more than its share — it hasn't shown up in how hitters are squaring him up.
Ian Seymour takes the ball for Tampa Bay as close to a mirror image: a 4.11 ERA that's actually 0.46 runs worse than his own contact quality earns him. The board has already moved with the mismatch — the total opened at 8 runs and has come in a full run to 7, even as Tampa Bay's own bullpen enters the day stretched thin, four relievers flagged unavailable off the last three days of work. Bieber's ERA already looks bad. The board is betting the version hitters are actually seeing is worse than that.