The Jets played with a patchwork cornerback duo in Saturday’s preseason game at the Bengals, since they were missing three of their top corners.

One of them, starter Dee Milliner, has officially been diagnosed with a high left ankle sprain, according to Jets coach Rex Ryan.

High ankle sprains can be notoriously difficult to recover from. Ryan said an MRI examination determined that Milliner had a high ankle sprain. The Jets have been encouraged by his progress so far.

“He’s being aggressive with his rehab and he’s progressing nicely,” Ryan said. “What that means, I guess we’ll see. But I know he is really attacking the rehab part of it, and he’s doing well. We feel confident that it’s healing nicely.”

After suffering the injury, Milliner initially wore a walking boot while on the sidelines at practice. At Monday’s practice, Milliner strolled down the sideline without a boot on. He walked with a noticeable limp, though.

The Jets’ other starting corner, Dimitri Patterson (calf/ankle/quadriceps), also missed Saturday’s game. Patterson has not practiced fully since the Aug. 7 preseason opener against the Colts. He was limited in Monday’s practice and did some individual drills, “which was encouraging to see,” Ryan said.

Ryan expects Patterson to be ready for the Sept. 7 opener against the Raiders.