ANAHEIM, Calif. — Los Angeles Angels ace Garrett Richards is expected to need surgery to repair a torn ligament in his right elbow, sidelining him into next season, a person familiar with the situation told The Associated Press.

The person spoke to the AP on condition of anonymity because the team wasn’t expected to make an announcement on Richards’ condition until later Friday.

Yahoo Sports first reported the apparently serious blow to the Angels, who have four potential starters sidelined in various stages of recovery from arm injuries.

The 27-year-old Richards made his first opening day start for the Angels last month, cementing his rise atop the staff since his breakthrough 2014 season. He is 1-3 with a 2.34 ERA in six starts this season, repeatedly facing other teams’ aces and getting meager run support from his light-hitting teammates.

The hard-throwing right-hander already had been scratched from his scheduled start Friday with arm fatigue. Long reliever Cory Rasmus is scheduled to take his place in the opener of the Angels’ series against Tampa Bay.

Richards went 13-4 with a 2.61 ERA in 2014 while often pitching spectacularly for the Angels, who finished with 98 wins and the majors’ best regular-season record. But Richards needed season-ending knee surgery that August after getting hurt while covering first base, and Los Angeles didn’t win a playoff game.

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Richards then went 15-12 with a 3.65 ERA last season, emerging as a dependable No. 1 starter. He signed a one-year, $6.425 million deal for the current season to avoid arbitration, and he won’t be eligible for free agency until the 2018 season.

The injury would be the biggest blow yet to the Angels’ suddenly beleaguered rotation, which had been one of the few areas with depth for a franchise with a poorly regarded farm system.

Los Angeles already is without injured starters C.J. Wilson and Andrew Heaney, while Tyler Skaggs still hasn’t returned from his own elbow ligament replacement surgery in August 2014.

Yahoo Sports also reported that Heaney has an injured ligament that could require surgery. The Angels didn’t immediately comment on Heaney’s condition.

Wilson, who is making $20 million this season, has shoulder tendinitis that has kept the left-hander off the mound for nearly two months. The Angels don’t know when he will return.

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Skaggs had been pitching in the minors until he was shut down last week to recover from biceps tendinitis.

The Angels are likely to be forced to recall right-hander Matt Shoemaker, who was sent to the minors last weekend after a poor April performance in their rotation.