USA Today's Tom Pelissero has heard free agent TE Dustin Keller (knee) is "on track to return."
Keller was having a huge camp in 2013 with the Dolphins before tearing his ACL, MCL, and PCL, dislocating his right knee in Miami's third preseason game. There's no telling what Keller has left -- the injury was gruesome and he's entering his age-30 season -- but it's good news for him. NFL teams would probably want to see Keller work out before entertaining signing him.
http://www.rotoworld.com/teams/nfl/mia/miami-dolphins