Curveball consistency will hook Mike Montgomery’s rotation spot

Mike Montgomery threw two pitches in Game 7 of the 2016 World Series — two curveballs, plotted below.

That one on the far right highlighted in blue, at about 77.4 mph and 10 inches break, was a weak dribbler to Kris Bryant for the final out Game 7. It was an important pitch for that reason, but even more important in the overall development of Montgomery as the Chicago Cubs fifth starter in 2017.

Those two pitches averaged -9.37 inches of vertical movement. In 2016, Montgomery averaged -7.44 of vertical movement, according to PITCH f/x leaderboards on Baseball Prospectus, good enough for 36th best among pitchers with at least 200 pitches thrown.

That isn’t bad, and worth keeping tabs on. Montgomery delivers a one-two punch of fastball and curveball primarily, throwing them a combined 65 percent of the time in 2016. His fastball is a big one, sitting around 93 in 2016, and the curveball has serious potential, as those two Game 7 pitches showed.

The trick the Cubs’ coaching staff will ask him to master is consistency.

Here’s a look at a monthly breakdown of Montgomery’s curve in 2016:

There’s a dip in July and August, which upon review of the game logs didn’t necessarily suggest a correlation with his spot starts or being traded from the Seattle Mariners to the Cubs.

Unlike what Jeff Sullivan at FanGraphs discovered with Rick Porcello’s curve last off-season, showing it improved with decresed velocity, Montgomery’s hook doesn’t seem likely to follow that pattern when paired with the data above.

With a mid-90s fastball, if the Cubs and pitching coach Chris Bosio are able to hone in consistently on that -7.45 average vertical break, Montgomery can make trouble. Consider that in conjunction with what Jared Wyllys of BP Wrigleyville wrote in November on Montgomery’s increased changeup usage. Notable in the article is his swing-and-miss rate (about 30 percent) against right-handed batters.

Another strong sign for Montgomery is a 58.4 percent groundball rate in 2016. Among pitchers with at least 100 innings pitched, Montgomery produced the third high GB% in baseball.

Montgomery’s curve produced grounders more than 61 percent of time a ball was put in play, according to Brooks Baseball, and the changeup at just more than 55 percent.

I looked for pitchers to match Montgomery’s repertoire against, and came closest on Gio Gonzalez.

About a half-inch separate the two in terms of vertical curveball movement, but on the surface layer, not much more.

If Montgomery can become more consistent with his already-good breaking stuff, while continuing to miss bats and get groundballs with his changeup and mid-90s heater, he seems to stand a reasonable chance to work into a current version of Gonzalez without the propensity for the long ball.

For a projected fifth starter, that is more than good enough. He might fall short in the end, but a fifth starter doesn’t need to be much more than decent, and Montgomery’s got a good shot at that.

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Jerry Burnes is a contributor Beyond the Box Score. You can follow him on Twitter at @jerryburnes.