In less than a week, Jon Kitna went from high school math teacher to backup quarterback for the Dallas Cowboys—and the 41-year-old already knows what he’s going to do with his game check.

Kitna spent 15 years in the NFL but formally retired from the league in 2011. He’s spent the last two years as a math teacher and football coach at Lincoln High School in Tacoma, Wash., where his son, a sophomore, plays quarterback. However, upon learning that starting quarterback Tony Romo would likely miss the Cowboys’ season finale due to an injured back, Kitna texted head coach Jason Garrett to offer his services as a backup, the Dallas Morning News reports.

“I told Jason if he wants me or somebody to come in and call a play and be able to pull a play off if a bad situation happened, I would be willing to do that,” Kitna said. The Cowboys will pay Kitna $53,000 this week for his services, but the NFL veteran won’t be keeping the money, the Dallas Morning News reports. Instead, he will donate his game check to Lincoln High School.

Kitna may have been out of the NFL for a few seasons, but he’s quite familiar with what the Cowboys expect of him. After all, he spent the last three seasons of his career as Romo’s backup and is well-versed in the team’s offensive scheme. At Wednesday’s team practice, he ran the scout team offense ahead of the Cowboys’ divisional clash with the Philadelphia Eagles, the Dallas Morning News reports.

“He said he would run scout team for the [Lincoln] high school team and give them a really good look like he gave us great looks when he was here,” Garrett said. “So he’s a very active guy. He’s a mentally tough guy. … And he’s certainly very young at heart. So it was good to have him back, good to have him back in the meetings, and [I’m] excited to see him practice today.”

In the event that Romo can’t play on Sunday, Kitna will serve as the backup to journeyman quarterback Kyle Orton. Kitna has thrown for nearly 30,000 yards and 169 touchdowns during his career.

[h/t For The Win]