DAVIE, Fla. -

Miami Dolphins left tackle Jake Long is hurt again.

Long left practice Monday after injuring his right knee during an 11-on-11 drill. He sat in a cart while being examined, then walked to the locker room. Coach Joe Philbin declined to discuss the severity of the injury with reporters.

Back trouble slowed Long last season, and he went on injured reserve before the final game because of a torn right biceps. He nonetheless was chosen a Pro Bowl starter for the third consecutive year.

Long has battled knee trouble in the past and wore a brace on his right knee Monday.

Rookie Jonathan Martin, who protected Andrew Luck at Stanford, moved from right tackle to the left side to fill in for Long.