The left-hander pitched five innings in the victory. According to the Los Angeles Times' Pedro Moura, Skaggs "felt a pinch in his right side" after striking out Joey Gallo and finished out the fifth before coming out of the game.
Skaggs is in his first full season back on the mound after Tommy John surgery forced him to miss the entire 2015 season and most of 2016 as well. Through five starts, he's 1-1 with a 3.99 ERA and a 3.40 FIP, per Baseball-Reference.com.
His absence will cause further problems for a starting rotation already hit hard by injuries. Andrew Heaney and Nick Tropeano will almost certainly miss the entire season after undergoing Tommy John surgery last summer, and Garrett Richards is on the 60-day disabled list with a right biceps strain.
With a 14-13 record, the Angels are only three games back of the Houston Astros for first place in the American League West. Maintaining that pace will be even more difficult with another starting pitcher out for an extended period of time.