Dolphins left tackle Jake Long left practice early Monday with what appeared to be a right knee injury.
According to ESPN, the Dolphins believe Long sprained his medial collateral ligament, and hes getting an MRI to determine the damage.
The Dolphins believe that if the sprain is determined to be mild, he could be out one to three weeks. If it's moderate, he could be out three to four weeks. The Dolphins are optimistic it's mild.
Long sat on the ground for a couple of minutes, clearly in pain, while the teams medical staff stood over him. He walked off, without assistance, grimacing but not limping.
Long then sat on a cart and was examined briefly by trainer Kevin ONeill. ONeill worked on the area between his knee and ankle while Long shook his head in disgust. Long and ONeill then left the teams practice bubble.
Asked if hes concerned about it being a long-term injury, coach Joe Philbin said, No, Im not, but I have no information. Even if I did, I wouldnt share it.
When Long left, Jonathan Martin moved to left tackle and guard Artis Hicks took snaps at right tackle.
If playing left tackle comes to pass, [Martin] has three or four years at Stanford at left tackle, Philbin said. Hopefully, we dont need to figure that out. You have to have contingencies.
Long, an impending free agent, was bothered by back problems last season and suffered a season-ending biceps injury in the next-to-last game of the season.
The Dolphins already are short-handed on the offensive line. Backup tackle Lydon Murtha and multi-position reserve Nate Garner were not at practice for the second day in a row. Murtha has been sidelined by foot pain. The reason for Garners absence remains undisclosed.
The Dolphins got down to the 75-player roster limit Monday by releasing speedy receiver and skilled special-teams player Julius Pruitt, who impressed the team during its offseason program but lost ground in training camp. Earlier, safety Kelcie McCray (foot) was placed on injured reserve.
In an odd twist, Pruitt was listed as a second-teamer on the depth chart the Dolphins released moments before cutting him.
I dont know if we had a harder-working guy on the ballclub, Philbin said. I thought a lot of him. It was hard.
Pruitts release leaves Miami with 10 receivers: Davone Bess, Legedu Naanee, Brian Hartline, Clyde Gates, Marlon Moore, Roberto Wallace, B.J. Cunningham, Chris Hogan, Rishard Matthews and Jeff Fuller.
Hartline has not participated in team drills for nearly a month because of a lingering calf injury. On Monday, he ran around cones and caught passes from receivers coach Ken OKeefe. Bess appeared to injure a finger Monday and was examined on the sideline.
The Dolphins also are expected to monitor the waiver wire for available receivers after NFL teams cut down to the 53-man roster limit by Fridays 9 p.m. deadline.
Philbin said quarterback Ryan Tannehill will play a little in Wednesdays exhibition finale at Dallas. Tannehills 13 drives this preseason have ended with 10 punts, one touchdown, one field goal and one interception. Ive done some good things at times and other times been inaccurate with the ball, he said Monday evening.
• Linebacker Karlos Dansby, who missed the past two games with a knee injury, suggested he would be ready for the Sept. 9 opener at Houston.