Ryan Kartje (LA Times)  —  Dennis Simmons had spent the better part of the last two decades coaching college receivers, so it was no small thing last fall, when he suggested that USC’s receiving corps was the deepest he’d ever coached. With so much talent, it seemed the biggest task facing the team’s receivers coach would be managing all the egos involved.

“Now I understand why Dr. Phil gets paid the amount of money he gets paid,” Simmons joked in August.

Four months later, the depth Simmons once enjoyed has since disappeared, leaving USC with glaring questions at a position that not long ago seemed like a strong suit.

USC’s two top receivers, Brenden Rice and Tahj Washington, made their intentions clear to declare for the NFL draft over the last week after accepting invites to the Senior Bowl and East-West Shrine game, respectively. Then, on Friday, Mario Williams entered the NCAA transfer portal, leaving USC without three of its four starters from last season.

Williams was the third USC receiver in the past week to enter the portal, joining Raleek Brown and Michael Jackson III. Once a five-star recruit, Williams followed coach Lincoln Riley from Oklahoma, only to watch his production diminish over the course of his time at USC. Last season, Williams was plagued by drops but finished with 29 catches, tied for third on the team.

Dorian Singer makes a one-handed catch against Nevada in September. (Wally Skalij / LAT)

In all, USC is now slated to lose at least 65% of its production at the receiver position.

That mass exodus leaves the Trojans with only two upperclassmen receivers entering the offseason, Dorian Singer and Kyron Hudson, neither of whom were able to establish a consistent role in 2023.

Singer arrived at USC as a top transfer last offseason from Arizona. But after leading the Pac-12 in receiving as a sophomore, he had only 276 yards receiving in his first year at USC.

It could mean USC is left next season with two sophomores as its top receivers, albeit both of them five-star talents. Zachariah Branch (1) might very well step into the No. 1 receiver role, after the electric freshman became the first Trojan to be named an All-American in his first year. Duce Robinson, meanwhile, finished tops on the team in average yards per catch (20.47) and flashed plenty of big-play ability as a freshman.

USC should add two more four-star receivers to the fold next week on national signing day in Ryan Pellum (Millikan High) and Xavier Jordan (Sierra Canyon).

Regardless, USC’s passing attack is bound to look different next season. It’s not even clear yet who will be throwing to the Trojans’ suddenly thin group of receivers.

Miller Moss will start the Holiday Bowl, but other dominoes could fall at quarterback in the coming days and weeks. One of the nation’s most coveted transfer quarterbacks, Kansas State’s Will Howard, visited USC on Friday.