Receiver George Farmer was not expected to be among them.
But Farmer announced Wednesday that he was leaving USC to turn pro.
"This was a hard decision, one I thought over long and hard," Farmer said in a statement. "I received input from my family and the coaches, and ultimately it was my decision. I feel like I am ready for the next level, so I am forgoing my senior year and I will work hard to prepare for the NFL."
Farmer informed Coach Steve Sarkisian of his decision Monday, the first day of spring semester classes at USC, and met with him Tuesday.
"I gave him my thoughts about him leaving USC early, the pros and the cons," Sarkisian said in a statement. "At the end of the day, he made his decision, so we will support him and wish him the best."
Farmer is the fourth draft-eligible junior to leave USC since the end of the season, joining defensive lineman Leonard Williams, receiver Nelson Agholor and running back Javorius Allen.
This season, after coming back from knee surgery that sidelined him in 2013, the former Gardena Serra High standout caught 25 passes, four for touchdowns.
Farmer's speed was on display in the Trojans' regular-season finale against Notre Dame. Farmer caught two touchdown passes, including one for a career-long 48 yards, in USC's 49-14 victory.
But coaches did not send him on deep routes in USC's 45-42 Holiday Bowl victory over Nebraska. Farmer caught one pass for four yards and finished his career with 30 receptions and four touchdowns.
Junior Darreus Rogers is now the dean of a position group that features sophomores JuJu Smith, Steven Mitchell and Ajene Harris. Sophomore cornerback Adoree' Jackson is expected to play a larger role on offense next season.
Rogers caught 21 passes, four for touchdowns, last season. Smith was second behind Agholor with 54 receptions, five for touchdowns. Mitchell caught seven passes, two for touchdowns, and Harris had four receptions.
Isaac Whitney, a transfer from Riverside City College, has begun classes at USC and De'Quan Hampton of Long Beach City College has committed to the Trojans.
Whitney caught 49 passes, four for touchdowns, and averaged 16.5 yards a catch, according to Riverside's website. Hampton had 64 receptions, seven for touchdowns, and averaged 13.1 yards a catch, according to Long Beach's website.