Walker, 38, began his 14-season NFL career with the San Francisco 49ers in 2006. He spent seven seasons with the 49ers before signing a four-year, $17.5 million contract with the Tennessee Titans in 2013.
Walker will make it official on Tuesday afternoon when he holds a press conference at Nissan Stadium in Nashville, Tenn.
"I would say it worked out better than I could have imagined," Walker said on Monday. "I dreamt about it, and made it come to life because I believed it would. I knew once I had the opportunity, I wasn't going to let it get away from me.