The Los Angeles Angels suffered a major blow Friday that could affect their chances in an already competitive American League West.

Right-hander Garrett Richards has a torn ulnar collateral ligament in his right elbow and is expected to undergo Tommy John surgery, according to multiple sources.

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The 27-year-old was scheduled to start Friday, but the club scratched him, citing dehydration and fatigue.

Passan reports the tear was found Thursday, and Richards will not return until the middle of 2017 if he decides to have the surgery. He's currently seeking a second opinion, but Angels officials believe the tear is too significant to rehab.

Richards, the ace of the Angels' staff, tossed 207 1/3 innings for L.A. last season and was expected to anchor their rotation.

The Angels have had a rough go this season when it comes to their starting pitchers: Both C.J. Wilson (shoulder) and Andrew Heaney (strained flexor) are currently on the disabled list, while Jered Weaver's velocity is down and Matt Shoemaker was recently demoted to the minor leagues.

Richards, a former first-round draft choice, owned a 1-3 record with a 2.34 ERA in six starts before the injury.

Over his six seasons in the bigs, Richards owns a 3.58 ERA and has twice led the league in wild pitches.