Michael Williams simply grew out of being a tight end.
Williams, a seventh-round draft pick a year ago after playing on three national-championship teams at Alabama, was listed at 6-foot-6, 270 pounds during his rookie season with the Detroit Lions.
But after spending a year on injured reserve because of a broken hand suffered in a preseason game, the move to offensive tackle was somewhat inevitable for him.
"Probably a natural," coach Jim Caldwell said. "He had to fight to keep his weight down. He came back (for the start of off-season workouts) and was somewhere in the neighborhood of 300 pounds. You don't see many 300-pound tight ends.
"I think it allows him not to worry about cutting weight all the time to kind of fit the position. He's a naturally big guy that can be a very athletic tackle."
Williams would have had trouble finding any playing time at tight end anyway after the Lions drafted Eric Ebron and re-signed Brandon Pettigrew to go with Joseph Fauria.
Williams said this is the first time he has ever played offensive line in his life.
"I was smaller, believe it or not, when I was younger," he said. "I played running back."
The transition, however, could go smoothly simply because he was known much more for his blocking as a tight end in college than his pass-catching ability.
This scenario reminds Williams of how his college career got started. He redshirted his first year at Alabama while playing linebacker/defensive end before moving to tight end the next season.
"I know how it goes," he said. "It's a different level but I've been through it before. It's not that big of an adjustment."
Caldwell has seen others during his long coaching career make the move successfully from tight end to offensive tackle.
He was an assistant coach at Northwestern, where Chris Hinton made the transformation and went on to be the No. 4 pick overall in the NFL Draft in 1983 and get selected to seven Pro Bowls in his 13-year career.
Caldwell was also an assistant at Louisville when Bruce Armstrong went from a tight end to getting drafted in the first round in '87 as an offensive tackle and was chosen for six Pro Bowls during a 14-year NFL career.
The difference is that those changes were made while the player was still in college. Williams needs to be on a much faster track here if he wants to win a roster spot as the No. 4 offensive tackle behind Riley Reiff (6-6, 313 pounds), LaAdrian Waddle (6-6, 321) and Corey Hilliard (6-6, 300).
Williams said he wants to add another 15-20 pounds "the right way."
"I don't want to just throw on 50 pounds of fat," he said.
Williams said the move didn't come as a surprise.
"It's been in the talks for a while," he said. "It was up to me to make the decision. I felt like I can prolong my career this way, with my body size, my skill set."
He's going to miss catching some passes, but Williams said he's looking at all the positives.
"You try to attack it with a negative attitude then you're going to end up sitting there and probably cut," he said.
For Williams, the most difficult aspect early on has been just getting his mind to make the necessary adjustments. He's had to fight his instincts as a tight end.
"I found myself listening to the pass part of (the play call) instead of protection," Williams said. "I actually messed up a play (last week in practice) doing that. I'll get used to it. I have to."
