Today the Chicago Cubs send right-hander Jake Arrieta out against the Washington Nationals in Game Four of the 2017 National League Division Series. As we examined this morning, his opponent, Tanner Roark, had an unusual development path as a prospect. Arrieta did as well, although in a different way. While Roark was an obscure prospect who made good, Arrieta was a top prospect who was initially disappointing but eventually found his stride.
Arrieta pitched college ball at Texas Christian and had an excellent 2006 season (14-4, 2.35, 111/37 K/BB in 111 innings). He was rated as a first-round talent by draft experts entering the spring of 2007, but experienced some control problems that spring (93/50 K/BB in 98 innings, 3.01 ERA) and had large bonus demands, which dropped him down to the fifth round. It took $1,100,000 for the Baltimore Orioles to sign him, well over slot value.
Assigned to High-A Frederick for 2008, he posted a 2.87 ERA with a 120/51 K/BB in 113 innings allowing just 80 hits. He was up to 97 MPH at times and showed promise with his curve, slider, and change-up, although his command still needed polish. I had him rated as a Grade B+ prospect entering '09.
He was very effective at Double-A Bowie in '09, with a 2.59 ERA and a 70/23 K/BB in 59 innings, but his command was occasionally troublesome after he moved up to Triple-A Norfolk, raising his ERA to 3.93 with a 78/33 K/BB in 92 innings. The slider drew good reviews but his curve and change-up needed more work, though he retained a Grade B+ rating entering '10.
Arrieta spent most of '10 and '11 in the major leagues with spotty results, posting a 4.88 ERA in 220 innings combined. Although his ERA shot up to 6.20 in 2012, his component ratios actually improved dramatically, his K/9 ratio going from 4.66 in 2010 to 7.01 in 2011 to 8.66 in 2012. His walk rate went down, too, going from 4.31 in '10 to 2.75 in '12. The improved components were reflected in his FIP, which was much lower than the ERA at 4.05.
Arrieta became a completely different pitcher in Chicago, posting impressive numbers in 2014 (2.53 ERA in 157 innings) then winning a Cy Young Award in 2015 (22-6, 1.77, 236/48 K/BB in 229 innings, ridiculous 215 ERA+, 7.3 fWAR). He’s been more human in 2016 and 2017 (combined 6.2 fWAR, 3.30 ERA in 365 innings, ERA+129) but is still an above-average pitcher.
Overall, Arrieta is 88-56, 3.57 ERA in 1161 innings, ERA+ 114, 22.2 fWAR.
To this point in his career, Arrietta’s Sim Score comparables include Mat Latos, Rich Harden, Chris Tillman, Steve Busby, Dave Boswell, Lance Lynn, Charlie Lea, Stephen Strasburg, Josh Johnson, and Ray Washburn. There are no bums there and some short-term aces (Busby and Boswell notably).
In a real sense it has been two careers: with the Orioles he had a 5.46 ERA in 358 innings, but with the Cubs it is 2.73 in 803.
That said, Arrieta was clearly making progress in his last season with Baltimore and the Cubs were wise enough to see it. About the worst thing you can say about Arrieta since joining the Cubs is that he’s thrown more than 200 innings just once.