In a season where there might not be a whole lot to cheer for, outside of the inevitable debuts of Travis d’Arnaud and Zack Wheeler and the continued maturation of Matt Harvey, something that Mets fans can take pleasure in is watching homegrown southpaw Jon Niese try to take the next step forward and bring himself into the next tier of starting pitchers.
Over the past three full seasons, we’ve seen Niese take some giant steps forward, improving his stock from fourth starter ceiling to a bona-fide number two starter and de facto ace of the Mets staff. He has done so by cutting his walk rate from a decent 3.21 BB/9 in 2010, to a stingy 2.32 BB/9 in 2012, while maintaining a strikeout rate of more than seven per nine innings.
The peripheral stats have always, at the major league level, indicated that Niese was a better pitcher than his win-loss record and ERA indicated.
He struggled with incredibly high BABIPs in his first two full seasons, posting a .324 mark in 2010 and .333 in 2011. For this reason, Niese had never been able to perform close to his FIP or xFIP marks. For example, in 2011, he posted a 3.38 xFIP, yet his ERA ended up at 4.40.
Last year, however, it all changed for Niese. Opponents had only a .272 BABIP, his ERA was better than his FIP, and he seemed to finally have everything click.
While it may be easy to simply write this off as luck or regression to the mean (the mean here being the .300 BABIP that serves as the approximate midpoint on the normal distribution), it is likely that a simple change in Niese’s approach is responsible for a significant portion of the improvement.
The most significant change for Niese last season was a lesser dependence on the four-seam fastball and a heavier dependence on the cutter.
In 2011, 54.9% of the pitches Niese threw were four-seamers, and his cutter accounted for 17.2% of pitches. In 2012, the four-seamer was only used 49% of the time, and the cutter was up to 27.8%.
Good thing too, because last season the cutter went from his worst pitch (-6.9 runs above average according to PITCHf/x) to his best (10.6 runs above average).
To put that in perspective, it was the best cutter in baseball last season by that metric. The next best belonged to Yu Darvish, whose cutter was valued at 7.3 runs above average.
The increased reliance upon such a dominant pitch could very well be responsible for the giant step forward Niese appeared to take last season, as well as his early season successes in 2013.
If Niese can demonstrate that the success of his cutter last year was no fluke, and can maintain a reasonable BABIP (somewhere in the .285-.305 range), there is no reason to doubt that he can indeed take another step forward in 2013 and become a legitimate ace, instead of just the by-default ace he is now.