Just seven months after signing with the Dallas Cowboys, defensive tackle Stephen Paea has decided it's time to retire. 

After spending the past few months battling through a knee injury, the 29-year-old decided this week that he wasn't capable of playing anymore. Paea went into Jason Garrett's office on Tuesday and informed the Cowboys coach that he would be hanging up his cleats. 

"He came in here and he had a knee injury that was preventing him from practicing and playing at the level that he felt like was up to his standard throughout his career," Garrett said Wednesday, via the Cowboys' official website. "We had a good conversation [on Tuesday] and he explained all that to me. He was working through it for the last few weeks trying to get himself back but simply wasn't able to do that."

According to the team's website, Paea had been dealing with a knee problem for most of the offseason. Despite the injury, Paea was still able to serve as the Cowboys' starting defensive tackle during their first four games of the regular season. However, Paea didn't play against the Packers in Week 5, and his decision to retire came two days after the team's 35-31 loss to to Green Bay. 

With Paea now out of football, the Cowboys don't have a lot of depth at defensive tackle. Although David Irving started in place of Paea against the Packers, he may not be the team's starter going forward. The Cowboys could either go with Irving or Brian Price. 

As for Paea, his retirement comes six years after he was selected by the Bears in the second round of the 2011 NFL Draft. Since then, the defensive lineman has played for four teams over seven seasons. 

Paea isn't the only 2017 free agent who will be leaving Dallas this week. The Cowboys also cut ties with Nolan Carroll, who signed a three-year, $10 million deal with the team in March. From a talent perspective, the move wasn't that shocking: The Cowboys are happy with their starter corners -- Orlando Scandrick and Anthony Brown -- and have been impressed with the play of rookie Jourdan Lewis. 

From a financial perspective, the move was somewhat surprising: Carroll will be leaving Dallas with a lot of money in his pocket. Although he only played in two games this season, Carroll will still get his full $3 million signing bonus.