Jake Arrieta was drafted in the 5th round of the 2007 draft and moved up through the minors relatively quickly, making his Orioles debut in 2010. With sub-3.00 ERAs at three of his four stops down on the farm, he made his way up the pitching prospect rankings. After getting a mid-season call last year, Arrieta is making it through his first full season at the Major League level. It is likely that Arrieta is owned in every deep mixed and AL-Only league, but the question becomes whether we may be witnessing a breakout season that would enable him to generate value in shallower mixed leagues.
Despite posting some impressive ERAs during his minor league career, his peripherals were nothing special during his time at Triple-A in 2009 and 2010. His control was mediocre to below average and his strikeout rates came in below 8.0, a level too low to really be considered a top pitching prospect. Unsurprisingly, he struggled over 100.1 innings for the Orioles in 2010, striking out only four more hitters than he walked, and punching out just 52 batters. His 4.66 ERA was not completely terrible for an American League rookie pitching in the AL East, but his 5.17 xFIP was a little more of a disappointment.
He posted a SwStk% of just 5.7% and a high Contact% of 86.3%, while throwing first pitch strikes and pitches inside the strikezone at rates below the league average. On the positive side, he did feature a four-pitch arsenal, which is a nice starting point for a young pitcher, especially when that includes a fastball that averaged nearly 93.0 miles per hour.
Turn the calendar to 2011, and so far this year Arrieta has reminded us that we cannot ignore a second year pitcher’s minor league numbers even if he displayed poor skills during his rookie season. He has upped his strikeout rate to 8.1, much more in line with what his High-A and Double-A results suggested, though better than his less inspiring Triple-A marks. His control has also been improved, but remains slightly worse than the league average. His career batted ball profile tells us he is pretty much ground ball neutral, though he induced ground balls in the high 40% range at two stops in the minors, which gives some reason for optimism here.
He has thrown his slider nearly five percentage points more frequently this year, primarily at the expense of his change-up. This is a welcome adjustment as his slider has generated the highest whiff rate of all his pitches and he has actually thrown it for a strike most often as well. This has resulted in an increased SwStk% to 7.8%; however, that still comes in below the league average, while his Contact% stands right at the league average. Given these metrics and his Triple-A strikeout rates, I would expect Arrieta’s K/9 to drop below 8.0 and likely finish in the low 7.0 range. His control, however, looks to have legitimately improved so I think he could maintain his current 3.7 BB/9.
He has posted a 3.74 xFIP so far, with a 4.03 ERA. Given my expectation for a decline in his K/9, I think his ERA should settle right around 4.00 where he currently sits. Though that would mean this is not a major breakout, it is a definite improvement from last season. Still, I think that would earn him only minimal shallow mixed league value, if any at all. Last, I wanted to point out that ZiPS is projecting a 5.20 ERA for the rest of the season which I think is pretty insane. He should handily beat that mark.