New York Yankees ace Gerrit Cole has a home run problem. What's going on?

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Gerrit Cole has a home run problem.

Look, the New York Yankees have plenty of issues, and Cole is hardly the biggest of them, but when you sign the most lucrative contract for a pitcher in baseball history, the expectations are skyscraping, especially in New York and for a storied franchise that has not been to the World Series since 2009.

Cole is 4-3 with a 3.63 ERA and 70 strikeouts in 52 innings heading into Thursday's start against the Orioles, who happen to be improbably breathing down the necks of the Yankees for the eighth and final playoff spot in the American League. As Cole has slumped so have the Yankees. He's 0-3 in his past four starts, and the Yankees have lost all four of those games in the midst of a 5-15 slump that led general manager Brian Cashman to head to Buffalo to give the team a pep talk. New York finally got back in the win column Wednesday.

The number that stands out for Cole is 13 home runs allowed. That rate over 212⅓ innings, which is how many he pitched for Houston in 2019, translates to 53 home runs. To put that in perspective, the only pitcher to allow 50 or more home runs in a season was Bert Blyleven, who allowed 50 for the Twins in 1986.

Cole entered the season as the consensus Cy Young favorite in the AL after a dominant campaign with the Astros in which he won his final 19 regular-season decisions and set a record for starting pitchers with a 39.9% strikeout rate.

What has happened?

It isn't just the home runs. Cole's strikeout rate, though still impressive, is down to 32.9%, his average exit velocity allowed has increased from 87.6 mph to 91.1 (which puts him in the bottom 10% of all pitchers), and he has pitched seven innings just once in nine starts after doing so 15 times in 33 starts last season.

Let's dig in to some of the numbers, starting with what has happened on those 13 home runs:

July 23: Adam Eaton, 2-2 count, 98.1 mph fastball (406 feet to RF)

Staked to a 2-0 lead over the Nationals in the top of the first, Cole wanted to go up in the zone but left the pitch middle-in, and the second batter he faced in his Yankees career hit it out.

July 29: Dwight Smith Jr., 0-0 count, 95.7 mph fastball (389 feet to RF)

This one came late in the game on Cole's 101st pitch with the Yankees holding a 7-1 lead over the Orioles. Smith turned on an inside fastball at the knees.

Aug. 3: Jay Bruce, 3-2 count, 98.7 mph fastball (418 feet to RC)

A third-inning home run that tied the game 1-1, this pitch was up in the zone, though over the middle of the plate, and the Phillies' Bruce knocked it into the bullpen at Yankee Stadium.

Aug. 8: Jose Martinez, 2-0 count, 96.1 mph fastball (428 feet to LC)

Cole really had to work against the Rays, as Martinez's home run came on his 107th pitch, even though it was only the fifth inning. Martinez was sitting fastball up in the count, and Cole threw one right down the middle.

Aug. 14: Alex Verdugo, 1-1 count, curveball (375 feet to RF)

As with the previous four home runs, the Yankees were ahead when Cole allowed this one. It was a curveball in off the plate, with a strike probability of just 21%, but Verdugo golfed it into the second deck at Yankee Stadium for the Red Sox.

Aug. 19: Ji-Man Choi, 2-1 count, changeup (413 feet to RC)

With this flat changeup on the outer third of the plate, Choi displayed impressive raw power by reaching for the pitch and crushing it well into the bleachers at Yankee Stadium. The second-inning home run gave the Rays a 1-0 lead.

Aug. 19: Mike Zunino, 1-2 count, 97.8 mph fastball (428 feet to CF)

This was an awful pitch to a bad hitter. Zunino hit .104 with two strikes in 2019. He's hitting .119 with two strikes in 2020. Catcher Gary Sanchez wanted the pitch away, but Cole threw this one dead center, and Zunino hit it out to center field.

Aug. 26: Ronald Acuna Jr., 3-2 count, 97.3 mph fastball (473 feet to LC)

Facing the first Braves hitter of the game, Cole threw a good fastball on the outside corner. Acuna didn't miss it, hitting a 114 mph rocket.

Aug. 26: Dansby Swanson, 2-1 count, slider (354 feet to RF)

Cole fanned Swanson earlier in the game with a steady diet of power sliders, and he threw a good one on 1-1 on the outside corner, but the umpire called it a ball. Cole came back with another slider, but it didn't move at all and hung up in the zone, and Swanson got enough to send it into the first row of seats. Really, this was the first semi-cheap home run Cole had given up.

Aug. 26: Marcell Ozuna, 1-1 count, curveball (469 feet to LC)

Two batters after Swanson, Ozuna gave the Braves a 4-0 lead with another mammoth home run off Cole's knuckle-curve that kind of rolled over the middle of the plate.

Aug. 31: Ji-Man Choi, 1-2 slider (360 feet to RF)

Choi didn't hit it all that hard -- at 95.3 mph, this is the "softest" of the 13 home runs -- but he snuck it into the second row of the short porch at Yankee Stadium to give the Rays a 2-0 first-inning lead. The hit made Choi 7-for-11 lifetime against Cole, with three home runs and three doubles. Go figure.

Aug. 31: Kevin Kiermaier, 1-1 count, 97 mph fastball (411 feet to RF)

"Gerrit Cole is kind of in shock right now," Yankees announcer Paul O'Neill said after Kiermaier's 110 mph blast on an inside fastball -- his hardest-hit ball of the season.

Sept. 5: DJ Stewart, 1-0 count, 96 mph fastball (353 feet to RF)

A towering fly ball to right field at Camden Yards -- with a 43-degree launch angle -- Stewart's first hit of the season broke a scoreless tie in the sixth inning. Cole then fell apart after an error extended the inning and allowed four unearned runs following Stewart's home run.

"I try to take the good stuff from it, but in the end, especially right now, I just feel like it wasn't good enough," Cole said after the game. "Some really nice pitches tonight, some really nice sequences, but in the end, when the pitches mattered, we kind of fizzled out."

Eight of the 13 home runs Cole has allowed have come on fastballs, but only two have come when Cole was ahead in the count. That's kind of what you might expect: Cole is still pretty untouchable with two strikes, so hitters will try to jump the fastball, especially when ahead in the count. Of course, that was the approach hitters used last year as well, when 17 of the 29 home runs Cole allowed came off his four-seamer.

As you can see from the pitch locations listed above, Cole's command within the strike zone hasn't been quite as elite as we've seen in the past, and he has left too many fastballs in hittable locations. His swing-and-miss rate on his fastball is what jumps out to me:

2019: 37.6%
2020: 25.0%

Fewer fastballs in the right location leads not just to fewer swing-and-misses but also to more counts favorable to hitters, which means they can sit on the fastball. Also, Cole's average fastball velocity is down a tick, from 97.1 to 96.5, which could be a minor factor.

Maybe he's simply throwing too many meatballs? We can tally the number of fastballs determined to be "mid-mid" of the strike zone -- meatball location, in other words. In 2019, 10% of Cole's fastballs were mid-mid; in 2020, it's ... 10%. So that's not the issue. (Batters are doing a little more damage on those pitches, however. In 2019, Cole allowed six home runs all season on mid-mid fastballs. He has already allowed four in 2020.)

The skeptics out there could suggest that Cole is missing the Astros' secret sauce -- their infamous ability to get pitchers to increase their spin rates on fastballs. This is what Trevor Bauer insinuated a couple of years ago, when he tweeted in reference to the Astros: "If only there was just a really quick way to increase spin rate."

Well ... Cole's spin rate on his four-seam fastball is down very slightly, from 2,530 rpms to 2,503. That doesn't seem like a big factor, but the vertical drop on his fastball has increased from 10.9 inches to 11.6, which means it isn't holding its plane quite as well. That's how you get so many swing-and-misses on those fastballs up in the zone.

These are all minor issues. It's also just nine starts. It's worth noting that through his first nine starts last season, Cole was 4-4 with a 3.88 ERA. He had one more bad outing a couple of starts after that, and then he went 16-0 with a 1.78 ERA in his final 22 outings.

Of course, Cole doesn't have four months to make his adjustments this year. He (along with a few of his teammates) needs to make them now.