Could this be it for Robey?

LOS ANGELES -- Nickell Robey has walked down the Coliseum tunnel for a USC Trojans home game 19 times in his three-year college career.

Saturday's 5 p.m. PT game against Notre Dame, then, will be his 20th. It also might be his last.

Robey, a 20-year-old junior cornerback, could leave for the NFL draft after this season. With three full seasons as a starter already on his resume, he's thought of as a potential second- or third-round selection, with his small size the biggest thing holding him back.

Because of that, Saturday's pregame festivities will have a much different feel to them, Robey said Wednesday. As one of four USC captains, he leads the Trojans down the tunnel before each game and starts the run onto the field, too.

"Yeah, it's going to feel different -- it's going to feel a lot different," Robey said. "Because you know something is ahead, and it's waiting for you and it's calling you out.

"You gotta answer to it sooner or later. That time will come one of these days in the future."

At a listed 5-foot-8 and 165 pounds, Robey will have to prove to teams he has the speed and instincts to overcome the limitations presented by his size. He was on his way to doing that after his sophomore season, but his play has fallen off a bit over the latter half of the 2012 season.

Still, he's a capable playmaker, highly agile in the return game and a far better tackler than most 165-pounders. So it's possible he'll be a valuable commodity over the next few months.

Robey said it hasn't even crossed his mind.

"To be honest, I really haven't been thinking about this stuff at all," he said. "I'm going to think about it later on. I'm going to get around my group of supporters and my important people. I'm going to look at different scenarios and different cases of where I stand.

"After the season, that's gonna get resolved. Decisions are going to be made."

Until then, Robey has to deal with the uncertainty of whether this will be his final home game, his final bowl game and so on.

Senior safety T.J. McDonald said he knows that feeling all too well. He had the same stuff in his mind a year ago, when he was contemplating leaving for the draft after his junior season.

"I know how stressful that situation is, so I'll stay away from him unless he wants to come to me for help," McDonald said. "But, Nickell, if he needs help, I'm always in his corner, he always has me.

"I'm definitely always there with open arms."

McDonald stayed but has seen his draft stock fall from a probable selection in either the late first or early second rounds to the second-or-third-round area he currently occupies, according to early 2013 mock drafts.

With undersized but experienced players like Robey, there's a common understanding that they can't do anything to make themselves taller or otherwise more physically appealing in another collegiate season.

So the smart thing to do, it's often said, is to declare for the draft and attack those deficiencies head-on at the next level.

Robey might decide to do just that, or he might channel McDonald and quarterback Matt Barkley and opt for a fun-filled senior season.

He has another two months to make that decision. And at least one more tunnel walk.