In his NFL debut, Mason McCormick made it into the game for one play — a placekick try.

During the Pittsburgh Steelers’ second game, McCormick jogged onto the field for three such snaps.

This past Sunday during Week 3 of his rookie season, McCormick rotated into the game on offense.

That gradual ascension is expected to continue this Sunday.

With starting left guard Isaac Seumalo listed as doubtful, McCormick is likely in line to make his first start during Sunday’s game at the Indianapolis Colts.

“I am confident in who I am,” McCormick said after Friday’s practice at UPMC Rooney Sports Complex. “I have worked really hard to put myself into this position, and so I am going to go out there and do what I need to do and play as hard as I can, and the rest will sort itself out.”

A fourth-round pick out of South Dakota State, during last week’s Steelers win McCormick played some “jumbo” tight end and rotated in at left guard with Spencer Anderson.

“It’s just good to get those initial nerves out of the way,” McCormick said, “just because there’s a little bit of an unknown never being in an NFL football game, and then it’s your first time. So to be able to get that out of the way gives me all the more confidence in the world, and I believe in myself and trust my coaches that I am ready to roll.

“Any time you get some experience and you do a good job, obviously your confidence goes up and it allows you to keep rising to the challenge.”

McCormick said family and former college teammates will be on hand Sunday at Lucas Oil Stadium.

If McCormick starts it will be to the left of another rookie, center Zach Frazier. A second-year player, right tackle Broderick Jones, is also in the starting lineup.

McCormick spent most of training camp playing with the second team at guard, most often at left guard. But in Seumalo and Nate Herbig, the Steelers are down two of their projected gameday veteran interior offensive linemen.

“I am super excited,” McCormick said. “Any time you get an opportunity to play this game, it’s a fun one. I look forward to the challenge, and whatever happens, happens.”