Gino Gradkowski has said that he will have to work to secure a place in the Baltimore Ravens' starting lineup.
The centre spent his first year in the NFL being mentored by Matt Birk, who announced his retirement earlier this week.
The 24-year-old told the Ravens' website: "I have mixed feelings. Matt's had a tremendous impact on my life in the last six months. He's just been a great influence on me.
"I was raised to believe that nothing is ever handed to you, and especially at this level. They're going to bring somebody in, and that's fine. I have to work for this spot. The way I see it is there's a job opening. I need to work my butt off this off-season to earn that spot.
"I think I gained a lot of confidence throughout the year. I got really good with the offense, the mental part of it and looking at defenses and things like that. Mentally is where I think I improved most my first year."
Gradkowski did not start a game during 2012 but came off the bench for all 16 regular season fixtures.
