Williams, a third-round pick in 2009, has struggled more than he's stood out for much of his career.
His nine receptions for 82 yards over two seasons aren't impressive and he hasn't had success as a returner in the kicking game. His four catches for 64 yards and a touchdown this preseason have been hurt by dropped passes.
Williams is well aware of what is at stake for him in Detroit's preseason finale Thursday night in Buffalo.
''Guys in my position have to show some things,'' he said. ''A lot of people say preseason games are like auditions, giving you and opportunity to add some tape to what you've done in the regular season.''
Williams isn't the only Lion hoping to hang on.
''It's going down to the wire,'' Detroit coach Jim Schwartz said. ''Both of those guys have punted very, very well.''
The Lions plan to play quarterback Matthew Stafford and the first-string offense briefly.
''They won't play that much,'' Schwartz said.
Stafford, though, insisted the exhibition will be meaningful when backups Shaun Hill, Drew Stanton and perhaps fourth-string quarterback Zac Robinson are playing with other reserves.
''It's a big game for our team to mold our roster,'' he said. ''There are some position battles that are going down to the fourth game.''
The Ndamukong Suh-led defensive front, likewise, will likely be on the sideline shortly after breaking a sweat. That's when defensive end Willie Young hopes to make the most of his opportunity to secure his place on the roster.
''I don't feel like I have a spot on the team yet,'' Young said. ''The last preseason game might be meaningless for the guy who plays a snap or two. But for a guy like me, every snap on the field is critical. I have to take advantage of the opportunity I'll have in Buffalo.''
Schwartz said it's not just jobs, but roles, that will be on the line when starters sit and backups play.
''There's still some guys that need to get looked at,'' he said. ''Those guys are competing for a job on this roster, those guys are competing for a job on other roster, they're competing against other people's rosters. That's a very real dynamic as you get late into training camp.''