The Facts: Following up on a previous item. ... Keller visited the Pats yesterday but left town without a contract, according to sources.

Diehards Line: Keller tore his ACL, MCL and PCL and dislocated his knee last August during a preseason game, but one source told Herald staffer Jeff How that Keller’s “knee is healed.” The 29-year-old is now focused on returning to football shape. Howe went on to suggest the 6-2, 255-pounder could be used similarly to Aaron Hernandez if he joined the Pats. Keller, a liability as a blocker, does his best work as a receiver so he would line up offset the line or in the slot. Depending on his explosiveness and mobility following the injury, the Patriots might also get creative with Keller in the backfield. ... If they sign him. Remember: Rob Gronkowski said Tuesday it was too early to know if he will be ready for Week 1 after tearing his ACL in December. Michael Hoomanawanui and D.J. Williams are the only other tight ends on the roster, and the Patriots are expected to spend an early draft pick at the position next week. That’s why they’re seeking to boost a position that made their offense so successful from 2010-12. ... Stay tuned.