For 29 long-awaited regular-season games, and 13 more in the postseason, Greg Bird looked like the hitter the Yankees had envisioned from the beginning -- a powerful left-handed first baseman tailor-made to slug in the Bronx.
After returning from ankle surgery on Aug. 26, the 25-year-old finished the year by cracking eight homers with an .891 OPS, and added three postseason homers with a .938 OPS as the Yanks made it to within a game of the World Series.
If Bird can carry that forward into 2018, he will become a major piece in the middle of a Yankees lineup that already looked poised to challenge the single-season team home run record. Even alongside mashers like Giancarlo Stanton, Aaron Judge and Gary Sanchez, Bird has the potential to hold his own.
The Statcast™ data for Bird points to the first baseman being a prime candidate to break out at the plate this season. He wasn't just cracking homers down the stretch in 2017 -- he was showing a hitting skillset specifically suited to a Yanks corner player with the short right-field porch in front of him. In other words: Bird was hitting the ball hard, in the air, to the pull side.

From the point he rejoined the Bronx Bombers through Game 7 of the American League Championship Series, 34 of Bird's 93 batted balls -- 36.6 percent -- were hard-hit air balls.
"Hard-hit air balls" includes any batted ball with an exit velocity of 95 mph or higher and a launch angle between eight and 50 degrees. Statcast™ uses that 95-mph threshold as the baseline for hard contact. And for air balls, the 8-50 degree launch-angle range encompasses line drives and fly balls while excluding ground balls and popups. That's the contact that can do damage. Essentially all barrels, for example -- the optimal quality of contact -- fall in that range of launch angles.
Since Statcast™ started tracking in 2015, more than 75 percent of all extra-base hits have had exit velocities of 95-plus mph and launch angles of 8-50 degrees. If you're hitting a lot of balls that hit those marks, you're likely to have success, and that's exactly what Bird did to close out the year.
Bird's rate of hard-hit air balls from August through the end of the postseason was the second-highest out of 344 Major League hitters with at least 50 batted balls in that timespan. The only player with a higher rate was Judge. That's good company to keep.
Highest rate of hard-hit air balls from Aug. 1 through postseason
95+ mph exit velocity; launch angle 8-50 degrees
Minimum 50 batted balls from Aug. 1 through postseason

1. Aaron Judge: 37.6 percent
   2. Greg Bird: 36.6 percent
   
2. (tie) J.D. Martinez: 35.1 percent
   
3. (tie) Khris Davis: 35.1 percent
   
4. Rhys Hoskins: 34.9 percent
   Nearly all of Bird's hard-hit balls were elevated. Even high exit velocities aren't nearly as damaging if the ball is pounded into the ground or skied straight up into the air. Bird stayed right in the sweet spot in between. Only three of his hard-hit balls weren't in the productive air-ball range. (All were grounders with launch angles below eight degrees; none were popups over 50.) No hitter elevated more of his hard contact than Bird, who put 91.9 percent of his hard-hit balls in the air from August onward.
   
   It's also a good sign for the Yankees that Bird's batted-ball trends between the regular season and postseason stayed extremely consistent. His rate of hard-hit air balls was 36.2 percent in August and September (69 batted balls, 25 hard-hit air balls); it was 37.5 percent in the postseason (24 batted balls, nine hard-hit air balls), the fifth-highest rate of the 61 hitters who had at least 10 batted balls in the playoffs. Bird put 92.6 percent of his hard-hit balls in the air down the stretch of the regular season (25 of 27); his rate was 90 percent in the playoffs (nine of 10), second only to Cody Bellinger among the 20 hitters with double-digit hard-hit balls last postseason.
   Highest rate of hard-hit air balls in 2017 postseason
   95+ mph exit velocity; launch angle 8-50 degrees
   Minimum 10 batted balls in postseason
   
5. A.J. Pollock: 40.0 percent
   
6. Daniel Murphy: 38.5 percent
   
7. Aaron Judge: 38.1 percent
   
8. George Springer: 37.7 percent
   5. Greg Bird: 37.5 percent
   The last thing to consider is Bird's spray direction, which makes for an especially dangerous combination with his batted-ball tendencies because of the team he plays for. A Yanks lefty's greatest advantage is the shallow right field in his home park. Largely thanks to that porch, hard-hit line drives and fly balls by left-handed hitters have left the yard 26.8 percent of the time at Yankee Stadium since the introduction of Statcast™, the third-highest rate of any MLB ballpark. And right field is exactly where Bird is driving the ball.

Bird pulled 43.4 percent of his line drives and fly balls in 2017, the 10th-highest rate of the 163 left-handed hitters with at least 50 batted balls of those types tracked by Statcast™. Also among the higher lefty air-ball pull rates were fellow Yankees Aaron Hicks (46.3 percent) and Didi Gregorius (37.5 percent), both of whom made good use of the short porch on their way to career years.
Highest pull rate on LD/FB, left-handed hitters in 2017
Minimum 50 tracked batted balls

1. Matt Olson: 49.2 percent
   
2. Ryan Schimpf: 49.0 percent
   
3. Brandon Moss: 48.5 percent
   
4. Aaron Hicks: 46.3 percent
   
5. Curtis Granderson: 45.9 percent
   
6. Joey Gallo: 45.1 percent
   
7. Asdrubal Cabrera: 44.4 percent
   
8. Mike Moustakas: 44.2 percent
   
9. Benjamin Zobrist: 43.6 percent
   10. Greg Bird: 43.4 percent
   Bird could be next. He profiles as the exact type of hitter you'd expect to thrive in pinstripes. A healthy Bird, playing a full slate of home games at Yankee Stadium, should be a force to be reckoned with.