When an injured pitcher makes his first start after a rehab assignment, he doesn’t usually throw a lot of pitches. When a pitcher hasn’t started in a couple of weeks, he doesn’t usually throw a lot of pitches. When a pitcher who has been working out of the bullpen most the year makes a start, he doesn’t usually throw a lot of pitches. This is common sense, and yet betting markets don’t seem to realize this -- at least not to the fullest extent.
The Rays’ Drew Rasmussen threw 71 pitches against the Boston Red Sox on Sept. 7 and struck out two batters. A no-name pitcher with a run-of-the-mill stat line wouldn’t normally be noteworthy, except that betting markets set his strikeout prop at 5.5 with an implied projection (after accounting for juice) of 5.16. My projection system, THE BAT X, projected just 2.49 strikeouts for Rasmussen. After all, he has been a reliever most of the year and has been kept to 60 or so pitches in most of his “starts.” Yet betting markets thought he’d strike out double his most likely outcome. This was one of the most egregiously inefficient strikeout props I’ve ever seen and is a perfect example of one type of edge that can be found for betting strikeout props.