Robey said Thursday that Luck has been receiving more fanfare than he deserves, relative to Barkley.
"I believe that people should probably look at Matt more, but that isn't something I can control," Robey said Thursday, after the Trojans finished their last practice in preparation for Saturday's game against Stanford. "I feel like they are real similar."
"They run almost the same style of offense, so you get to see almost the same stuff that Barkley does as Luck. You gotta really study those guys in order to find something different about them, to me."
Through seven games this season, Barkley has completed 68 percent of his passes for 2,006 yards, 19 touchdowns and just four interceptions. Luck has completed nearly 72 percent of his throws for 1,888 yards, 20 touchdowns and only three interceptions. The players have been sacked a combined six times between them and have won 13 of 14 starts.
The only hiccup was USC's September loss to Arizona State, when Barkley threw two interceptions, the only time this season either player has done so.
Luck is being looked at as a current Heisman Trophy favorite. Barkley has occasionally been in the discussion but rarely finds himself in analysts' top-10 lists. Robey indicated that's probably off-base.
"I look at Barkley every day in practice like I'm looking at Luck, because they have almost have the same style of play," Robey said. "They're smart, they make the right decisions.
"They're not that different to me. They're not too different."
Robey, a sophomore, shut down Notre Dame's Michael Floyd last week to the tune of just four catches for 28 yards and picked off Tommy Rees to seal the USC win over the Fighting Irish in the fourth quarter. He said he has been studying film of Luck non-stop since USC got back from South Bend on Sunday.
USC receiver Robert Woods said he hasn't done enough research into Luck's play this season to make an adequate comparison between the two. But he, like many Trojan teammates, put Barkley's play up with the best of the best this season.
"I really haven't checked out Luck," Woods said. "I'm just with my quarterback Matt and I just see that he's a great quarterback and he's doing his job as a leader and putting the ball where he needs to be.
"I just see Barkley and I see he's doing well."
Pedro Moura covers USC for ESPNLosAngeles.com.