According to Aaron Wilson of the Baltimore Sun, since Ravens tight end Ed Dickson hasn’t signed his restricted free agent tender, he signed an offseason participation agreement so he can work out with his teammates during their OTA’s.
Tight end Ed Dickson hasn't signed his restricted tender yet, but did sign offseason participation agreement to take part in practices
— Aaron Wilson (@RavensInsider) May 22, 2013
The agreement protects Dickson in case he gets injured, since he currently doesn’t have a contract. He’ll eventually need to sign the tender, or sign an extension with the Ravens.