It’s a new season and a new, and deep, pool of receivers for USC

Like a teacher on the first day of school, USC assistant coach Tee Martin anxiously awaited the arrival of the Trojans’ receivers.

The initial position-group meeting of training camp was at hand. Martin had mentally outlined his presentation.

But as he surveyed the room in the McKay Center, Martin recognized an unexpected detail.

“I was like, ‘Wow, we need more chairs,’” he said.

After scrambling last season with only a few physically sound scholarship receivers, USC now has an abundance.

Junior Nelson Agholor and sophomore Darreus Rogers are back after solid 2013 performances. Junior George Farmer appears fit again after sitting out last season following knee surgery.

Freshmen JuJu Smith, Adoree’ Jackson and Ajene Harris are expected to contribute immediately and another newcomer, Rahshead Johnson, shows promise.

Junior Victor Blackwell has made several big plays in scrimmages and redshirt freshman Steven Mitchell is gradually showing signs of regaining the burst that made him a dynamic threat before a season-ending knee injury.

Coach Steve Sarkisian described the depth at the receivers position as “a luxury” as the Trojans prepare for their Aug. 30 opener at the Coliseum against Fresno State.

“It’s just finding the right rotation,” he said.

Quarterback Cody Kessler is reveling in the long lines of receivers during drills.

“It’s so weird for me to see,” he said. “I’m used to one or two guys going and then some of the walk-ons jumping in.

“Now we have numbers.”

Martin joined the USC staff before the 2012 season, coming over from Kentucky to join former head coach Lane Kiffin. He inherited a receiver corps that included All-American Robert Woods and Marqise Lee, who would go on to win the Biletnikoff Award as college football’s top receiver.

Woods left for the NFL after the 2012 season, but depth was not regarded as an issue when the Trojans opened spring practice in 2013. Then Farmer suffered a season-ending knee injury. During a players-only summer workouts, Mitchell also suffered torn ligaments.

Lee injured his shoulder during training camp, suffered a knee injury against Arizona State and aggravated the problem and was sidelined in the second half against Notre Dame.

During critical late possessions against the Fighting Irish, USC lined up with Agholor, Rogers and walk-ons.

So Kessler is looking forward to having plenty of high-performance options this season.

“Everyone can make plays,” he said of the receivers. “Everyone knows they can win one-on-one matchups.”

Agholor is a preseason honors candidate and is expected to be Kessler’s top target. The junior from Florida has eclipsed 100 yards receiving in a game three times.

“For me, it’s all about understanding concepts and understanding mismatches,” Agholor said.

Rogers caught 22 passes last season but is still looking for his first touchdown. The former Carson High star switched from No. 84 to No. 1 this season and is eager to make a name for himself in a jersey number once worn by former All-American Mike Williams.

Farmer has enjoyed a productive training camp, hauling in several long touchdown passes and making catches in tight spaces. He said his surgically-repaired left knee was stable and that he had attained pre-injury speed.

“It just feels good to be out here competing with no setbacks,” he said. “Everything is moving forward.”

While Farmer has waited more than three years for his opportunity, the freshmen will be fast-tracked into games as part of Sarkisian’s high-paced, no-huddle offense.

Smith has been dominant at times during practices, hauling in several long touchdown passes, catching balls over the middle and outmuscling defenders in the air.

Jackson worked mainly at cornerback before he suffered a foot injury that caused him to be sidelined for nearly a week. But with Josh Shaw and Kevon Seymour entrenched as starters, Jackson’s role on offense as a multipurpose threat will probably expand because Sarkisian does not want to waste a potential offensive weapon.

Harris has been, perhaps, the biggest surprise. Smith and Jackson arrived more heralded because they were regarded as huge gets on national signing day in February. But Harris, who played quarterback at Crenshaw High, has been a dynamic pass-catcher and playmaker.

Johnson, regarded as a potential cornerback as well, also is coming on.

As of late, so has Blackwell. He caught an 80-yard touchdown pass play in the Trojans’ first scrimmage last week.

“He has the ability to get behind defenders to create big plays and he’s shown more consistency than he did early on in training camp,” Sarkisian said.

Coaches are patiently monitoring Mitchell.

“He’s not quite 100% yet,” Sarkisian said, “but he is working his way back.”

Martin has been impressed by the group’s effort.

“Some guys get hurt, some guys get better, some guys retain information and some guys don’t,” he said. “Training camp sorts it out.”

gary.klein@latimes.com

Twitter: @latimesklein