New York Yankees starter Michael Pineda has a UCL tear, Tommy John surgery likely

Yankees starting pitcher Michael Pineda reacts during a start against the Blue Jays. (AP)

As the New York Yankees prepare to get the second half of the 2017 regular season underway, they'll have to do so without one of their top starting pitchers.

Michael Pineda, New York's 6-foot-7 strikeout machine, has a partial tear in his ulnar collateral ligament (UCL), and may require Tommy John surgery, Brian Cashman told reporters on Friday.

Pineda will seek a second opinion before deciding whether to get the season-ending procedure, Cashman said, but the recommendation is for Tommy John. Pineda hadn't mentioned anything about discomfort in his right elbow until a few days after his latest outing on July 5, when he allowed five earned runs in three innings at home against the Blue Jays.

The Yankees will enter Friday's series opener against Boston with Jordan Montgomery taking the hill, after he was optioned to Triple-A days before the All-Star Break. Luis Severino will square off against Chris Sale on Saturday, and for Sunday's double-header, Bryan Mitchell will start the first game and Masahiro Tanaka the second.

In 17 starts for the Yankees, Pineda went 8-4 with a 4.39 ERA. He struck out 92 batters and walked 21 over 96 1/3 innings of work, and was pitching to a 3.39 ERA after his first 12 starts of the year.

Cashman remarked that top pitching prospect Chance Adams would not be ruled out as a potential reinforcement for the Yankees rotation should Pineda opt for surgery, after the 22-year-old right-hander has put together a sensational season so far in the minor leagues.

In 17 starts this year, six in Double-A and 11 in Triple-A, Adams has gone 10-3 with a 1.94 ERA while amassing 96 strikeouts and 37 walks over 92 2/3 innings. Adams ranks seventh among Yankees prospects per, and was named by Baseball America as the No. 56 prospect in all of baseball through the midpoint of the season.