Source: Cowboys sign Michael Sam

— -- The Dallas Cowboys have signed Michael Sam, who is seeking to become the first openly gay athlete to play in the NFL, to their practice squad, a source told ESPN.

Cowboys coach Jason Garrett is expected to announce the signing Wednesday at his news conference scheduled for 11:30 a.m. ET.

With a definite need for pass-rush help, the Cowboys are bringing in Sam, who had three sacks in the preseason for the St. Louis Rams, for an extended look to see if last year's co-SEC Defensive Player of the Year at Missouri can potentially help a defensive line that needs help.

Sam will be assigned No. 46 with the Cowboys, sources told ESPN. This will complicate any potential jersey sales, since Sam will not wear that number if he is activated to the Cowboys' 53-man roster at any point.

Sam was among final group of players released last weekend by the Rams and went unclaimed off waivers. The Cowboys brought the defensive end in for a physical, and now will see what he can provide.

Sam was not on the Cowboys' draft board in May. Dallas had five seventh-round picks and did not select him.

ESPN.com Cowboys reporter Todd Archer and ESPN.com's Darren Rovell contributed to this report.