Meanwhile, safety Nick Collins, who sustained a sprained knee Nov. 4 against Kansas City, practiced with the first-team defense today, and is expected to start Thursday night against the Cowboys.
"I did everything (in practice)," said Collins. "I went in the ones, did team drills and individual drills. Everything was nice."
Rouse injured his knee late in the first half of Green Bay's 37-26 win over the Detroit Lions on Thursday. He is not expected to practice this week and probably will not be activated for Thursday night's game. The Packers do not have to reveal the status of their injured players until Tuesday, according to the league office.
Underwood spent two seasons with the Packers. He saw action in all 16 games in 2005 and spent all of 2006 on injured reserve.
Underwood was released in training camp and kept himself in condition at his home in San Diego. Underwood had a handful of other teams recently (Houston, Denver and Seattle) The Packers called him on Friday, and thrilled to be back in Green Bay.
"I seen the number (on his cell phone) and thought 'I hope this is who I think it is,'" Underwood said with a smile. "I was excited."
Cole had seen action in seven games this season and collected 13 tackles before he sustained a fractured left forearm Thursday at Detroit.
The Packers also signed cornerback Joe Porter to the practice squad and released safety Tristan Burge.
Porter, a 5-foot-10, 198-pound rookie from Rutgers, played in 44 games, including 11 starts, for the Scarlet Knights. He also participated in track, where he was the 2006 BIG EAST indoor and outdoor 200-meter champion.