EAST RUTHERFORD -- Robert Martin was playing Call of Duty when he got called to duty.

On the Sunday morning after the NFL Draft, as he tried to put out of his mind the uncertainty ahead, Martin was playing video games with a few of his former Rutgers teammates when the phone rang with a tryout offer for Giants rookie minicamp.

"This is a real big opportunity for me," Martin said Saturday before the second of three practices. "I want to show them that I can play and I haven't reached my peak yet. I want them to see my mindset is to work and make a play when my name is called."

The Giants' backfield includes No. 2 overall pick Saquon Barkley, promising second-year pro Wayne Gallman and veteran Jonathan Stewart on a two-year contract.

But there is an opening for a fourth halfback, especially after the Giants released Paul Perkins (injured) and Terrell Watson last week and didn't sign an undrafted free agent for the mix. Jalen Simmons, who has no NFL game experience, is the only other halfback on the 90-man roster.

"I try not to even worry about that," Martin said. "I need to make every rep count that I get. I'm doing what the coaches tell me to do, being in the playbook and taking this environment in."

Mincamps -- with no pads and no tackling -- are designed for running backs to shine, and Martin looked good hitting his holes and catching passes during his first NFL practice.

"Competing in everything I do helped me," Martin said. "The film doesn't lie. There were a lot of ups and downs at Rutgers, but when you press play on the film I'm going to give it 110 percent every chance I get."

Including on kickoff and punt teams, which he played even as Rutgers' starting running back.

"I played defense in high school, so I have no problem hitting anybody," Martin said with a big smile. "I'm trying to do whatever I can to get my foot in the door."

Martin finished 10th in Rutgers history with 2,256 rushing yards and ran for 18 touchdowns, but his two best seasons were his first two playing in a pro-style offense similar to the Giants' scheme under first-year head coach Pat Shurmur.

"It's just like the old offense we used to run," Martin said. "It's a real good feeling. I'm picking it up pretty fast."

After three Penn State-Rutgers head-to-head battles, Martin suddenly is in the same meeting rooms as Barkley. They both went to high school in Pennsylvania and nearly were Rutgers teammates "in a crowded backfield" before Barkley flipped his commitment.

"We're going to get each other better," Martin said. "He's from PA and I support every PA back. We've been keeping our head in the playbook, helping each other."

On certain practice reps, Barkley and Martin are taking handoffs from former Michigan quarterback John O'Korn. That's a lot of Big Ten blood.

"There are a lot of Big Ten players here, and it's a good feeling to know you played in one of the best conferences in the world," Martin said. "It prepared me. The Big Ten speed of the game got me ready for this right now."

The Giants have 36 tryout invitees in minicamp and only two or three typically will be added to the offseason 90-man roster.

"This isn't a tryout (where) they do or don't make it and it's over," Shurmur said. "The players need to understand they are here because they saw something that we really liked. Even though the 90-man roster might look a little different (Sunday), those guys are on the list of guys we might consider going forward."

Martin had exposures to Giants scouts at Rutgers Pro Day, the Giants local Pro Day and TEST Football Academy's Pro Day, where he trained five times per week after his senior season.

"I put in a lot of hard work, so I know hard work is eventually going to pay off sooner or later," Martin said. "All I've had to do my whole career is be consistent. When you are consistent, you have success."

Ryan Dunleavy may be reached at rdunleavy@njadvancemedia.com. Follow him on Twitter @rydunleavy. Find our Giants coverage on Facebook.

