Arguably, last year was Mariano's worst year as a reliever. While his peripheral stats were close to career highs (9.34 K/9 after a 6.6 K/9 in 2006, and a miniscule 1.51 BB/9) opponents set career highs against him with a .248/.296/.350 line.
My gut is to blame most on this on opponents Batting Average on Balls In Play (BABIP). For Mo this jumped to .335 the highest of his career by nearly .030. Just like a the spikes and trenches of a hitter's BA, a lot of this depends on the defense and the luck of the game. I expect Mo will regress toward the mean and post a BABIP around his .279 career mark.
But I was playing around with a new Fangraphs feature that tracks what pitches a pitcher throws, percentages of how often he throws them, and average MPH. I don't really care about MPH because I know that movement is more important.
But check out Mo's percentages. In 2005, he threw the cutter 54.8% of the time. In 2006, he only used the cutter 43.4% of the time. Last season, he threw the cutter for 73.2% of his pitches.
There's some chicken and egg here; did Mo use the cutter more because hitters were squaring up his other pitches, or did they figure out the cutter was coming and had trouble hitting it (hence the resurgence in K/9), but when they could get the bat on the ball they did more damage?
Has anyone else seen anything written recently about Mo's approach to hitters? For a pitcher who once told Tom Gordon that if the batters can't get hits, the pitcher doesn't have to adjust, the leap to nearly all cutter last season is very peculiar.
Just one more thing to keep an eye on this season.