Washburn was not at Edison Field for Tuesday night's game against the Oakland Athletics as he is being given time to deal with the situation.
He is supposed to start Thursday's final game of the crucial series as the Angels continue to battle Seattle for the AL wild card spot and are challenging Oakland for the AL West title.
The 28-year-old lefthander has racked up a 17-5 mark this season with a 3.32 ERA and has been a huge part of Anaheim's success this year.
Jarrod Washburn is accused of sexually assaulting a 16-year-old.(CP Photo)
Television station KABC reported a 16-year-old girl called police from an Orange County hospital room on September 1 and made the allegation.
The Angels' organization refused to discuss the situation in detail.
"We are fully cooperating with authorities regarding this issue." the team said in a statement. "Out of respect for all parties involved, any additional comments would be inappropriate."
Washburn has compiled a 45-25 mark over five seasons in the majors.
If he cannot start Thursday, the Angels will probably go with rookie Mickey Callaway.
"It is unfortunate and not uncommon that public figures have to deal with allegations of this nature," said Washburn's agent Scott Boras.
