A fourth-round pick of the Lions in 2010, Fox appeared in eight games with three starts in 2013. In three years before 2013, Fox appeared in only five regular-season games, with no starts.
Pro Football Focus gave Fox a +4 pass blocking grade in 205 snaps last season. He played right tackle exclusively for the Lions, including three starts at the position. His week 17 game against the Vikings was the only game Fox played every snap. In short, signing Fox would be done for tackle depth and not to have him start at right guard.
As things stand now, the Chiefs will have Eric Fisher start at left tackle and Donald Stephenson at right tackle. Jeff Linkenbach was signed for depth at tackle and guard, and has an outside chance at being the starting right guard. Fox would presumably fill the swing tackle position Stephenson filled last year.
Signing Fox would also take away some pressure for the Chiefs to draft an offensive lineman. Kansas City has only six picks so the more flexibility they have to select the “best player available” the better.