OXNARD, Calif. -- Cowboys defensive tackle Tyrone Crawford will miss practice for a second straight day, coach Jason Garrett announced Monday.

Crawford is dealing with a back issue and underwent an MRI on Sunday. Crawford's back recently started bothering him, but it's something he's experienced previously in his career, Garrett said. On Sunday, Garrett had said Crawford would miss practice as a precaution because the tackle was coming off shoulder surgery.

"We have a good plan for him," Garrett said. "We'll take the situation day-by-day."

It's concerning news for a defensive line that is already dealing with more than its share of suspensions and injuries. End Randy Gregory is on the reserve/did not report list. End Benson Mayowa and tackle Maliek Collins are on the physically unable to perform list. DeMarcus Lawrence is practicing, but will miss the first four games for violating the NFL's substance abuse policy.

In Monday's first padded practice, the first team defensive line looked like this: left end David Irving, tackle Terrell McClain, tackle Jack Crawford, right end Ryan Russell.

Crawford, 26, is entering his fifth season. He signed a five-year contract extension in 2015 worth $45 million. Crawford's five sacks last season make him the team's leading returning sack leader with DeMarcus Lawrence (eight sacks) suspended for the opening four games and the Cowboys' decision not to re-sign Greg Hardy (six sacks).

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