Twins left-handed relief pitcher Jose Mijares has long been a highly-rated prospect, with a low-90s fastball and an excellent slider. He appeared to live up to the hype as a rookie in 2009, posting a 2.34 ERA.
Ah, but wait.
Mijares' FIP was 4.01 last year. His xFIP was even worse at 4.43.
Those numbers suggest that Mijares was one of the luckier pitchers in baseball last year.
So, is Mijares a very good pitcher, or is he just an average pitcher who benefited from good fortune in 2009?
A quick glance at Mijares' two big "luck" indicators points overwhelmingly toward the latter.
His BABIP was .266, and he stranded 89 percent of runners. Most pitchers strand about 70 to 75 percent of runners, a range that Mijares typically sat in while in the minors.
So it's safe to assume that he got some stranded runners luck.
Being a "stats guy," it would be very easy for me to just say, "And his .266 BABIP is bound to regress to around the .300 average" and end this article.
But that's not all I have to say about the Twins' hefty lefty.
Due to his weight, Mijares hides the ball well in his delivery, and it's been statistically shown that pitchers with deceptive deliveries can sustain lower BABIP figures than most.
Indeed, Mijares put up a .253 BABIP across two levels in 2007 and had a .111 figure in his brief MLB stint in 2008.
The biggest component of BABIP is line-drive rate, because at around 70 percent, liners fall in for hits far more often than any other type of batted ball.
Mijares' 11.8 percent liner rate was second lowest in the majors last season.
Given this ability to keep batters from squaring up the ball, Mijares' low BABIP isn't a surprise.
My Expected BABIP formula has his 2009 at .265—one point below the .266 he actually posted, and trailing Colorado's Matt Daley by .004.
It's probably a bit much to ask Mijares to be in the top five in preventing liners year after year, particularly since the statistic is fairly volatile, but I'd be surprised if he wasn't consistently above average in that department from here on out.
When we look at the big picture of Mijares, then, we have to concede that he may not be a 2.34 ERA-quality pitcher (very few pitchers are), but he also isn't the 4.43 ERA pitcher his xFIP claims he is.
My True ERA numbers, which take batted balls into account, have him at 3.66 for 2009. Given his relative inexperience, one can expect him to improve a bit and post a low-to-mid-3s ERA in 2010.