McClain signed a one-year deal with the Ravens last year, but then announced his retirement in May 2013.
After being arrested, the 24-year-old spent time at his old college before deciding to return to the game, and is expected to join up with the Ravens for their off-season programme on Monday.
"I'm real excited to have Rolando back, one of my old teammates and a guy I battled with and went to war with every day," Cody told the Baltimore Sun.
"To have him back with me is awesome. He's ready to do what he's got to do to get back on the field. He's humbled himself a lot.
"The previous things he's been through, I think he's learned from them and is ready to move on."
McClain was drafted in the first round of the 2010 Draft by the Oakland Raiders.