Sarkisian is taking an indefinite leave of absence, athletic director Pat Haden said.

Haden announced the decision Sunday after Sarkisian didn’t attend practice.

Offensive coordinator Clay Helton will take charge of the Trojans (3-2, 1-2 Pac-12), who have lost two of their last three games. USC visits Notre Dame on Saturday night.

Haden wasn’t specific about the reasons for Sarkisian’s absence, only saying that “it was very clear to me that he is not healthy.” Haden spoke to Sarkisian by phone Sunday, and he asked the coach to take a leave.

Sarkisian publicly apologized before the season after he showed up drunk at a pep rally and made a slurred public statement. He announced he would be getting unspecified treatment, but didn’t believe he had a drinking problem, blaming his unsteady appearance on combining alcohol and medication.

Sarkisian is 12-6 during his short tenure leading the talented Trojans, who lost 17-12 to unranked Washington last Thursday. Sarkisian had been on the road recruiting during the weekend.

Helton is in his second stint as USC’s interim coach. He led the Trojans to a Las Vegas Bowl victory in 2013, a calendar year in which the Trojans had four different head coaches.

Sarkisian, a former BYU quarterback who played in the CFL, was an assistant under Pete Carroll on the Trojans’ great teams of the previous decade. Coaching alongside Lane Kiffin, Sarkisian ran USC’s offense before getting hired by the University of Washington to take over a winless program in 2009.

Sarkisian rebuilt the Huskies into a regular bowl team, but couldn’t lift them among the Pac-12’s elite. The Torrance, California, native left Washington to return to USC after Haden fired Kiffin five games into the 2013 season and then told interim coach Ed Orgeron that he wouldn’t get the full-time job.

Helton coached the Trojans for one game after Orgeron quit in disappointment, and Sarkisian kept the veteran coach on his new staff, which includes five coaches who worked with Sarkisian at Washington.

Sarkisian went 9-4 in his first season at USC, losing a handful of big games but showing promise in the final year of the school’s NCAA-mandated scholarship restrictions. In the first recruiting cycle after the sanctions ended, Sarkisian and his staff signed the nation’s consensus top class last February.

The Trojans were ranked No. 8 in the preseason AP Top 25 and picked to win the Pac-12 in a media poll, but the talent-laden team has been unimpressive since rising to No. 6 in the rankings last month. USC gave up 41 points in its first loss to Stanford last week, and the offense was inept throughout its five-point loss to the Huskies.