NEW YORK — Now what? The New York Yankees were depending on Clarke Schmidt to be a big piece of their rotation, but now he “likely” will have Tommy John surgery, according to manager Aaron Boone. If that’s indeed the case, he’ll be sidelined for the rest of the season — and likely most of next year, too.

How will the Yankees replace Schmidt? With the July 31 trade deadline fast approaching, should they fill the job internally with a prospect such as Cam Schlittler? Or should they acquire a starting pitcher?

The answers may not be clear, but Schmidt’s fate seems apparent.

“I think it’s pretty much inevitable,” Boone said before Saturday’s game against the New York Mets.

For general manager Brian Cashman, replacing Schmidt won’t be an easy task no matter which route he chooses. The 29-year-old righty has been one of the Yankees’ better pitchers, especially lately. He was 4-4 with a 3.32 ERA in 14 starts. He had a 2.18 ERA over his previous seven starts, which included not allowing a hit over seven innings versus the Baltimore Orioles on June 21.

Schmidt left his start against the Toronto Blue Jays on Thursday night after three innings and 55 pitches. He was placed on the 15-day injured list Friday with right forearm tightness and scheduled to undergo an MRI. Schmidt would be the second Yankees starter to undergo Tommy John this year, with ace Gerrit Cole missing the season after having the surgery in March.

The Yankees expect to get Luis Gil (right lat strain) back sometime after the All-Star break. The 2024 American League Rookie of the Year should provide a major boost. They also hope to have Ryan Yarbrough (oblique strain) back at some point after the break. Yarbrough had a 3.83 ERA in eight starts before getting hurt.

But Max Fried, Carlos Rodón and Marcus Stroman have lengthy injury histories, and Will Warren is a rookie. A chance for further volatility within the group of starting pitchers remains.

The Yankees could promote Schlittler, 24, who was their No. 8 prospect entering the season according to The Athletic’s Keith Law. He is 2-1 with a 4.18 ERA in five starts at Triple-A Scranton/Wilkes-Barre, striking out 13.3 batters per nine innings while walking 3.4. Schlittler is likely their starting pitching prospect most ready for the majors. Righty Brendan Beck, 26, has made just three Triple-A starts but has a 2.93 ERA. They likely don’t want to turn back to struggling veteran Carlos Carrasco, though he does line up with Schmidt’s next turn through the rotation. Allan Winans has a 0.90 ERA in 11 games (nine starts) at Triple A, and he gave up four runs in 4 1/3 innings in his only big-league start this season.

“He’s been really good,” Boone said Friday of Schlittler. “He’s exciting. He got some really good opportunities in spring training where we got to see him a lot, even making a start for us late in spring. He’s really impressed. He’s come fast. He’s done a really good job and certainly put himself in the mix with a great start at Double A, really good start at Triple A when he got moved up. Had a rough one his last time, but he’s an exciting pitcher.”

Trading for a high-end starting pitcher might prove difficult. Teams competing for the best arms often are willing to sell off their high-end prospects, and it’s unclear who the Yankees would want to trade, and for whom. Shortstop George Lombard Jr., 20, appears to be their prospect who comes closest to wearing the “untouchable” label. The Yankees have a bevy of young arms they could look to deal, and they recently promoted former top prospect Spencer Jones to Triple A.

The Yankees likely would have interest in Miami Marlins righty Sandy Alcantara, who has struggled this season but still seems to have the stuff (97.3 mph average fastball) to be a front-line starter. Alcantara is signed through next season and has a $21 million team option for 2027.

The Athletic’s Big Board (version 1.0) of players who could be traded before the deadline featured four starting pitchers in the top 10. They included the Milwaukee Brewers’ Freddy Peralta, Alcantara, the Arizona Diamondbacks’ Zac Gallen and the Orioles’ Zach Eflin.

The A’s reportedly “can’t wait” to trade righty Luis Severino, who would be plenty familiar to the Yankees, but the two years and $42 million remaining on his deal after this season will scare off lots of teams.

It seems unlikely that the Yankees would go into the deadline worrying that one of their top arms (Fried, Rodón) will get hurt and need to be replaced, and they probably view Gil’s return as equivalent to a big deal. Of all the scenarios, it may be most likely that if the Yankees look for an upgrade, it would be toward the middle or back end of the rotation.

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