After the Dallas Cowboys signed him to be the backup quarterback for Sunday's winner-takes-all match, 41-year-old Jon Kitna announced this week that he will be donating all his salary to the high school where he teaches mathematics.

Kitna, who played three years as a backup for Tony Romo before retiring in 2011, will make his return in Sunday's ballgame against the Philadelphia Eagles after the Cowboys signed him to back up Kyle Orton.

The veteran signal-caller will pocket $53,000 for playing his role in that game, and he told the Dallas Morning News that he's going to donate all of the money to Lincolm High School in Tacoma, Wash., where he teaches math.

"The Cowboys tried out a few quarterbacks but ultimately decided on Orton, mainly because of how familiar he is with coach Jason Garrett and the current system. Kitna apparently texted Garrett when Romo's back issue popped up and let him know he'd be available." CBS Sports NFL writer Will Brinson stated in his article.

Kitna admitted that he texted the Cowboys head coach about his availability once he learned that Romo suffered a back injury last Sunday. And he got a shot at making an impact in the Cowboys' most important game of the season.

"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 via CBS Sports.

Garrett said he was surprised to receive Kitna's text message, but he nevertheless believed the veteran was capable of playing his role because of his mental toughness and experience playing in Garrett's system.

"He said he would run scout team for the high school team and give them a really good look like he gave us great looks when he was here," Garrett said via CBS Sports. "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."

The Cowboys are scheduled to meet the Eagles on Sunday as both teams look to seal a spot in the postseason.