Smith told SI.com's Don Banks this week that he had decided in January to play one final season with the Panthers and then retire to spend time with his family next offseason.
"My knee was sore and I knew all the work I had put into my career and what it would take," Smith explained. "I came to terms with it, that this year was going to be my last year ever playing football."
Now that his knee is feeling better, Smith has already opened eyes in Baltimore.
"I love him," coach John Harbaugh told Banks. "There's guys in the league you hope some day to get a chance to coach, and he's been one of those guys for me.
"And now that we have him out here, he's exactly who he presents himself to be. He is who he says he is, and that's the thing I love about him. There's no BS there. This is the guy we wanted, and he's in heaven right now. I think what he's seeing is this really fits him well, especially the competitive part of him."
It's an excellent fit for Smith. Freed from the deep-threat role that no longer suited his aging legs, he can work the underneath crossing routes, slants and comebacks that Joe Flacco needed last year in a possession receiver.
Smith's 12,197 receiving yards are 19th all-time. If he does indeed play out the three seasons in Baltimore, there is a chance he will jump into the top seven or eight.