Former NFL running back Trent Richardson signed with Alliance Birmingham of the Alliance of American Football (AAF), the league announced Wednesday. 

Richardson, the third overall pick in the 2012 draft, hasn't played an NFL regular-season game since 2014. The 28-year-old ran for 2,032 yards and 17 touchdowns over three seasons.

Prior to arriving in the NFL, Richardson was a star for the Alabama Crimson Tide, finishing third in the 2011 Heisman Trophy voting. Speaking with AL.com's Matt Zenitz, he said he was looking forward to playing in the state of Alabama again.

"Excited about this," Richardson said. "Another opportunity for my professional career. Happy to be doing something that I really love doing, especially in Alabama and in Birmingham, which is a home away from home for me."

AAF co-founder Bill Polian told ESPN.com's Darren Rovell in July the league would look to capitalize on any local college connections with incoming players, citing Richardson specifically.

"If the Birmingham team has Trent Richardson, we think that will be something that would be a significant gate attraction," Polian said.

Richardson is the fourth former Alabama player to sign with Alliance Birmingham, joining quarterback Blake Sims, offensive tackle Dominick Jackson and Bradley Sylve.

The AAF will launch with eight teams in February 2019.