With Brett Anderson officially in the fold in the Cubs’ starting rotation to begin the season, Mike Montgomery slid back into a bullpen role in which he has performed admirably since arriving in Chicago.
He was on the mound when the Cubs closed out the World Series, and he was right back out there in a tied game in the 9th inning on Sunday against the Cardinals. Clearly, Montgomery has manager Joe Maddon’s trust. (Even if the results on Sunday (0.2 IP, 2 BB, 1 K, 2 H, 1 ER) were not ideal.)
Based on his pitch selection, it is evident Montgomery went through a bit of an evolution phase after joining the Cubs. Before moving into the rotation, Montgomery made seven relief appearances after coming over in a trade that sent prospect Daniel Vogelbach to the Seattle Mariners.
Montgomery’s pitch mix (in percentages) was as follows, courtesy of BrooksBaseball.net:
- 40.6% fourseam
- 5.6% sinker
- 10% changeup
- 27.5% curveball
- 16.3% cutter
However, things changed when Montgomery joined the rotation on August 20. That began a five-start audition for Montgomery where we saw changes in his pitch selection:
- 45.9% fourseam
- 2.6% sinker
- 11.81% changeup
- 27% curveball
- 12.6% cutter
Fewer sinkers and cutters, but more four-seamers from Montgomery during a run in which he limited opposing batters to a .190/.303/.405 slash line with 24.2 K% and 14.1 BB%. Not bad, but that walk rate was rather alarming.
The biggest change was still yet to come for Montgomery, as his return to the bullpen after those five starts revealed an adjustment:
- 44.5% fourseasm
- 3.6% sinker
- 8.4% change
- 42.2% curve
- 1.2% cutter
What stands out here is Montgomery’s newfound reliance on a one-two fastball-curveball punch, while trending away from his cutter and changeup. The increase in curveball usage makes the most sense, considering he coaxed batters into a 46.9% whiffs per swing rate and induced a 68.4% groundball per balls in play rate on curves. Montgomery’s curve is a valuable pitch because it has a propensity to miss bats often and induce weak contact when batters do get around on it.
There isn’t much doubt about Montgomery’s stuff. In a January piece in which FanGraphs’ Alex Chamberlain used arsenal score (explained here by Eno Sarris) in an attempt to identify potential breakout candidates based on groundball and strikeout tendencies, Montgomery stood out. The lefty ranked in the top-10 in arsenal score, which is eye-opening in its own right. And it all makes sense when you consider Montgomery used four pitches with the Cubs that induced grounders at a 55 percent clip or better to go along with the swing-and-miss potential of the curveball.
Perhaps Montgomery’s highest and best value – at least right now – is in serving multiple roles in the bullpen. He will be forever known as the pitcher who recorded the final out in the Cubs’ World Series championship-clinching win in a short-relief stint, but he also has showed the ability to be useful in multi-inning appearances in 13 of 23 relief appearances in Seattle, and did so four more times with the Cubs.
Even if the Cubs were planning to go with a strict five-man rotation, Anderson’s injury history suggests Montgomery (or some other pitcher) will be in line to start at least some games in 2017. But for now, Montgomery’s skills have a ton of value in the bullpen.