Los Angeles Angels ace Garrett Richards has a torn ulnar collateral ligament in his right elbow and is expected to need Tommy John surgery, a source with knowledge of the situation told Yahoo Sports.

The 27-year-old Richards, one of the hardest-throwing starters in the major leagues, would miss the remainder of the season and not return until the middle of 2017 should he undergo the procedure.

The tear was found Thursday, when the Angels scratched Richards from his scheduled Friday start citing dehydration and fatigue.

Richards, who hadn’t been feeling significant pain in his elbow, is the latest Angels pitcher to suffer from arm problems. Left-hander Andrew Heaney is on the disabled list with what’s been called a strained flexor muscle, though multiple sources told Yahoo Sports he has a damaged UCL as well and is rehabbing with hopes of avoiding Tommy John. Left-hander C.J. Wilson also is on the disabled list with shoulder issues.

The emergence of Richards into a frontline starter over the last two seasons bolstered the Angels’ hopes of contention this year. In six starts, Richards had posted a 2.34 ERA. That came on the heels of a strong 2015, in which he threw 207 1/3 innings following a season-ending knee injury in 2014, his breakout year.

Richards is expected to seek a second opinion following the initial diagnosis, though Angels officials believe the tear is too significant to try and rehabilitate it.

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