In a minor Tuesday afternoon roster move, the Vikings have released linebacker Nathan Williams and signed Stanford Keglar to take his place.

Williams, an undrafted free agent out of Ohio State, underwent offseason ankle surgery and started training camp on the Physically Unable to Perform list. Last week, coach Leslie Frazier sounded optimistic that Williams would soon come off the PUP list. But his progress was obviously not significant enough at this point.

Keglar was with the Vikings during their offseason program but was released in late June to make room on the roster for Desmond Bishop. The 28-year-old Keglar has experience with both the Titans and Texans but hasn't played in an NFL game since 2010.

With Bishop still dealing with a groin pull and starters Erin Henderson and Chad Greenway not likely to play much, if at all, in the Vikings' preseason opener Friday, the signing of Keglar adds additional depth to help the defense get through this week's game against Houston.