Hilliard’s agent, Blake Baratz, confirmed the deal via Twitter. Financial details weren’t immediately known.
Hilliard, 27, has been a priority for the Lions this offseason with the pending free agency of starting right tackle
"I think he did a really good job for us when he was here and had one start for us, I think against Kansas City in 2011," Detroit Lions general manager Martin Mayhew said of Hilliard after the season.
Hilliard is a six-year veteran who was signed by the Lions in 2009 off the Cleveland Browns' practice squad. He started four games for the Lions in 2010 and one in 2011.
"This year he didn’t play, just because Jeff (Backus) and Gosder (Cherilus) stayed healthy and Riley was ready to go, so he didn’t get an opportunity to get on the field, but he’s definitely a guy we try to get back."
Hilliard's signing, along with the expected restricted free agent tendering of Fox, could indicate the Lions are ready to go younger on the right side of their offensive line.
Reiff, who played as a sixth offensive lineman last year, will start at either right guard or one of the two tackle spots. Hilliard or Fox will be in the mix at right tackle.