On Wednesday, the Chicago Cubs traded for left-handed starter "pitching infrastructure," which has done some good work in the restoration department over the last couple years. Three pitchers in particular, Scott Feldman, Jason Hammel and Jake Arrieta, have all seen their fortunes improved significantly after joining Chicago and working with pitching coach Chris Bosio.
| Player | ERA Pre-Cubs | ERA with Cubs | FIP Pre-Cubs | FIP with Cubs |
|---|---|---|---|---|
| Jake Arrieta | 5.46 | 2.71 | 4.72 | 3.13 |
| Jason Hammel | 4.80 | 2.98 | 4.33 | 3.19 |
| Scott Feldman | 4.81 | 3.46 | 4.56 | 3.93 |
In the table above, all three pitchers saw a significant improvement in their ERA and Fielding Independent Pitching (FIP) after joining the Cubs.
| Player | WHIP Pre-Cubs | WHIP with Cubs | K/BB Pre-Cubs | K/BB with Cubs |
|---|---|---|---|---|
| Jake Arrieta | 1.47 | 1.05 | 1.74 | 2.72 |
| Jason Hammel | 1.44 | 1.02 | 2.09 | 4.52 |
| Scott Feldman | 1.41 | 1.22 | 1.72 | 2.68 |
And that chart shows all three pitchers saw a big improvement in their WHIP and strikeout-to-walk ratio (K/BB) once they joined Chicago.
Arrieta has seen the biggest improvement, with a big drop from his career ERA of 5.46 to 2.71 this season, and his FIP down from 4.72 to 3.13. Hammel, before his trade to Oakland, had seen his K/BB ratio improve dramatically, from 2.09 to 4.52. Striking out more hitters while walking less of them is kind of a good improvement to make. And Feldman's numbers improved across the board as well.
So what has Chicago done to help these pitchers get their games on track?
In the case of Hammel, he started throwing his slider (32.8%) far more often this year than he has throughout his career (18.8%). He's also throwing his curveball much less (5.9%) than he ever has (11.6%), which helps account for the best K/BB rate of his career.
For Arrieta, he is throwing his fastball less (46.6%) than he ever has in his career (58.9%). He's also almost totally stopped throwing his slider (just 1.2% of the time, compared to a career 12.1%) and has become more reliant on his cutter, which he's thrown 28.1% of the time this season, much higher than his career average of 5.7%. That has resulted in a career-low walk rate for the 28-year-old right-hander.
As for Feldman, he didn't appear to alter his repertoire much in the 15 starts he made for the Cubs in 2013, but his fastball suddenly became more effective, a career-best 1.31 runs above average on that pitch last season.
The Cubs have also done great work turning Ryan Dempster (5.01 pre-Cubs ERA, 3.90 post-Cubs ERA) and Paul Maholm (4.36 pre-Cubs ERA, 3.74 Cubs ERA) into solid starting pitchers, and helped get Travis Wood to an All-Star Game last year.
Felix Doubront needed a change of scenery as much as any player in baseball. He'll get that now with Chicago, a place that has been good for a lot of pitchers in a situation similar to his.