As spring workouts progressed, Chan Gailey stressed that observers shouldn't read too much into the team’s depth chart. The Bills coach keeps track of his players by putting their names on magnets, which can be easily moved at any time.

That depth chart carries more significance at the start of training camp, but there are still a few magnets that still could be moved.

Gailey addressed Buffalo's top position battles late Wednesday afternoon, again emphasizing their fluid nature.

As expected, Donald Jones will begin camp as Buffalo’s No. 2 wide receiver -- but the competition for the “Z” receiver spot remains wide open. Jones is competing with Derek Hagan and Marcus Easley for the starting job. Competitions at left tackle (Cordy Glenn vs. Chris Hairston) and backup quarterback (Vince Young vs. Tyler Thigpen) remain open as well.

“Donald will start there but, still, we’re looking at everybody,” Gailey said. “We’ve not ruled anybody out at this point at that spot. You’ve got to have somebody that walks out there the first day and you all will write about it and talk about it, but we’re going to move people around at different times during camp to try to get equal reps at left tackle, try to get equal reps at quarterback. Just because a guy starts the first day doesn’t mean anything. There’s some spots that we understand, there’s competition and we’re going to try to make sure that we make it as equal as possible going into the season.”

The Bills also have to determine their defensive line rotation in the coming weeks. Mario Williams is entrenched as a starter on the left side, but Mark Anderson, Chris Kelsay and Shawne Merriman are all vying for reps on the right side.

“I’m not ready to go there yet,” Gailey said. “I think different guys will play in different situations. So I don’t know that we’ll say that we have two guys that are going to start and they start every snap of every game. There will be a rotation that we’ll have there. How it goes, I don’t know yet. I know who the left end will be, but I don’t know who the right end will be.”

In other news, the team signed defensive end Sean Ferguson, an undrafted free agent out of Mississippi State who participated in the team’s May rookie camp on a tryout basis. To make room for him, Buffalo released defensive end Lionel Dotson.

Buffalo also placed tight end Mike Casussin on the Active/PUP list.

For more updates, follow Bills correspondent Mark Ludwiczak @CBSSportsNFLBUF and @MarkLud12.