Antonio Cromartie is an incredible athlete. He has long legs and is a big strider. Once he picks up speed, he looks like a world class sprinter. This was on full display in the Playoffs against the Colts as Cro broke a pair of 40 yard returns, one in the final minute that gave the Jets a realistic chance to win.
Brad Smith very well might not be back in green and white next season. There well could be a search for a new return man. That could be an extra argument to bring Cromartie back.
On the other side of the coin, the Jets might not want to expose a starting corner to injury over the course of a long season. It is one thing in the Playoffs where every extra yard could be the difference between advancing and going home. Jason Sehorn comes to mind, though, in the regular season. The Jets might save him for big spots.