Dennis Kelly had lower back surgery Monday and is out at least for the rest of the preseason.

The 6-8, 321-pound offensive tackle had to be helped into his truck Thursday. He's trying to figure out what went wrong although he felt something towards the end of last year.

"We're not really sure when it exactly happened," said Kelly, who started 10 of 13 games last season. "It wasn't like I got hit or anything like that. Then it died down in the offseason so we didn't think anything of it."

Kelly said he hoped it would "heal naturally" but rest didn't help.

Kelly said the surgery was to the L2 vertebra.

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