Leading up to the 2014 season, Zach McAllister looked like a prime candidate for regression. The 26-year-old posted a 3.75 ERA last season, but allowed a 1.36 WHIP, a .295 BABIP, a 4.03 FIP and a 4.53 xFIP.
McAllister wasn't a very big strikeout guy—6.8 K/9 in 2013—and averaged nearly half as many walks—3.3 BB/9—leading one to wonder whether or not he could maintain a sub-4.00 ERA over the course of another full season. However, over his first two starts, McAllister has done a lot to displace those concerns.
Through two starts—11.2 innings pitched, the Illinois prep product looks like a significantly different pitcher, allowing a 2.31 ERA and a 1.29 WHIP with season averages of 8.5 K/9, 3.1 BB/9, 2.75 K/BB and 8.5 H/9.
It can be difficult to build an argument for a breakout season on two starts, but there are signs that McAllister could be headed toward a career-defining season as opposed to the regression I once saw for him.
First, McAllister has boosted his strikeout rate while subsequently decreasing his walk rate and hits allowed. McAllister's strikeout percentage has increased by 5 percent while his walk rate has decreased by 0.3 percent.
What's most impressive about these improvements is that they have all taken place while his BABIP has skyrocketed from .295 last season all the way to .324 in 2014. Because of these changes, McAllister has seen his FIP and xFIP decrease by 1.75 and 0.22 points, respectively.
McAllister's 2.28 FIP puts him in the "excellent" category in FanGraphs.com's explanation of FIP and marks a stark departure from last season's mark of 4.03. In fact, to this point, the young righty has been worth 0.4 fWAR, the highest mark of any pitcher on the team's active roster—per FanGraphs.com.
Whether he can maintain these improvements has yet to be seen. However, the metrics he's posted to this point suggest that he may have turned a major corner in his development as a starting pitcher.