The 4 Most Valuable Rookie Pitchers in 2017

While Aaron Judge has grabbed the headlines as baseball’s most impressive rookie hitter, a teammate of his has quietly been their top rookie hurler.

24-year-old southpaw Jordan Montgomery has a 3.65 ERA over 16 starts for the Yankees this season and leads all rookie pitchers in WARP (1.7). He is also tied for the lead in fWAR (1.6) and is second, behind Kyle Freeland, in rWAR (2.0, compared to Freeland’s 3.1).

In addition to Montgomery, a trio of Rockies newcomers have helped put Colorado in prime position to grab a wild card berth.

Here are the top four most valuable rookie pitchers of the first half, as ranked by fWAR.

Jordan Montgomery, New York Yankees

fWAR: 1.6
ERA (ERA-): 3.65 (83)
FIP (FIP-): 4.05 (89)

Had it not been for Luis Severino’s breakout, Montgomery would have been the Yankees' most reliable pitcher in the first half, as the 24-year-old has outperformed the likes of Masahiro Tanaka, Michael Pineda, and CC Sabathia.

The southpaw has been a whiff machine through his first 91 big league innings, posting a 22.8% strikeout rate, and is tied for the seventh-highest swinging strike rate in the Majors (13.5%).

Opponents have swung at 37.0% of the pitches he has thrown outside of the strike zone (which ranks third in the game) and have made contact on these swings fewer than 55% of the time (his 54.8% O-contact rate is 12th-lowest, per FanGraphs).

His curveball has been his best pitch, as opponents have just a 57.3% contact rate against it, which is the 10th-lowest rate among the 59 pitchers who have thrown at least 200 curves this season, according to PITCHf/x data at Baseball Prospectus.

Opposing hitters have also had trouble squaring up the pitch, as they are hitting just .179 with a .077 ISO against Montgomery’s curveball.

On all his pitches, Montgomery has allowed a better-than-average exit velocity of 86.7 miles per hour. His .301 Expected wOBA also ranks 38th among the 148 pitchers who have allowed at least 200 balls in play, per Baseball Savant.

As a predominantly fly ball pitcher (only eight hurlers have a higher fly ball rate than Montgomery’s 43.1%), he has allowed a slightly worse-than-average 1.28 home run per nine innings rate despite a lower-than-average home run per fly ball rate (the league average rate is 1.27).

Montgomery’s home run to fly ball rate is 11.5%, more than two percent lower than the Major League average, and while this has helped keep his FIP above average, home run to fly ball rate tends to be prone to randomness.

Still, even if we normalize his rate, he would still be around a league average pitcher, as his xFIP- is 100, and his strikeout and walk rates (7.4%) are both above average. Montgomery has done well to reduce the free passes he allowed, as after allowing a 10.9% walk rate in April, he walked 7.4% and 6.4% of the hitters he faced in May and June, respectively.

German Marquez, Colorado Rockies

fWAR: 1.6
ERA (ERA-): 4.36 (86)
FIP (FIP-): 3.97 (85)

While much has been made about Colorado’s pitchers finally “hacking” Coors Field by embracing the ground ball, Marquez has actually bucked this trend.

The 22-year-old righty had just a 41.6% ground ball rate (below the league average of 44.3%), and much of his success is due to home run suppression on contact. This is a dangerous game to play in the thin air, but through his 76.1 innings this year, Marquez has not been burned just yet.

Among the 119 pitchers who have thrown at least 70 innings, only 11 players have a lower home run per fly ball rate than Marquez’s 9.2% (at home, this number is 13.5% but just 6.0% on the road).

The Statcast data suggests this is not all skill; according to xStats.org, Marquez “should have” allowed 10 home run this season, which is two more than he has allowed in reality. This means his xHR/FB% is 11.5%, between his real figure and the league average. Still, had Marquez allowed 10 home runs, his FIP would be 4.19, which is not too shabby for someone who calls Coors Field home (his xFIP is 4.64 and his xFIP- is 108).

As for his other skills, Marquez has a subpar 20.1% strikeout rate but an above average walk rate (7.8%).

Jeff Hoffman, Colorado Rockies

fWAR: 1.5
ERA (ERA-): 4.15 (82)
FIP (FIP-): 3.48 (75)

Hoffman is essentially Marquez, but with more strikeouts and fewer walks. He is the other Colorado starter who evidently did not get the memo about ground balls, as his grounder rate is 39.8%.

His homer per nine rate is just 0.80 over 56.1 innings, thanks to a 7.4% home run per fly ball rate that is tied for the eighth-lowest among the 154 big leaguers who have thrown at least 50 innings.

The 24-year-old former first-round pick’s xHR/FB% is 9.9%, while his xFIP- is 104; like Marquez, a combination of luck and skill seems to be at play.

Hoffman’s other peripherals have been solid, as he is sporting a 21.5% strikeout rate and 6.9% walk rate. Sustained success here should blunt the negative effect of home run regression, though both numbers have been in decline.

The reduced strikeout rate has fallen in conjunction with a drop in swinging strike rate, as batters are chasing fewer pitches and making contact more frequently on pitches inside and out of the zone.

If these trends continue, it is obviously a huge concern. If it just a blip however, Hoffman should keep on providing value for the Rockies.

Kyle Freeland, Colorado Rockies

fWAR: 1.3
ERA (ERA-): 3.77 (74)
FIP (FIP-): 4.76 (102)

Finally, a Rockies rookie who has allowed a lot of ground balls!

The lefty and former first-rounder owns a 55.0% groundball rate, helping the 24-year-old keep the ball in the yard. Despite a 12.6% HR/FB percentage that is close to league average, he has allowed just 1.01 home runs per nine. Unlike his teammates, Freeland’s actual home run rate is higher than his xHR percentage, as he has surrendered 12 home runs, which is one more than what would be expected based on Statcast data.

The low home run rate has kept his park-adjusted FIP around league average, despite brutal strikeout and walk rates. His 5.2% strikeout-minus-walk rate is the second-lowest among qualified starters, ahead of only Matt Cain. Freeland has struck out 14.0% of opposing batters (the 5th-lowest rate) while walking 8.8% of them (tied for the 19th-highest).

He has out-pitched his peripherals thanks to an unsustainably high 77.9% strand rate and a .287 BABIP. Some of the latter figure could be due to contact management, as his xBABIP is .292 and his 81.4 miles per hour exit velocity on grounders is tied for 22nd lowest (out of the 105 pitchers who have allowed at least 100 ground balls).

In any case, Freeland has already thrown 107.1 innings with a roughly league average park-adjusted FIP and that has value. Provided he can keep the ball on the ground and in the yard, this could continue (though some improvement in the strikeout and walk departments would certainly be nice).