The Tennessee Titans’ “No. 1 goal is to make sure (Marcus Mariota) is under center when we open up opening day,” head coach Mike Mularkey said today.

In a posting on the team’s website, the Titans said the quarterback’s availability for off-season workouts that start next month “remains uncertain” but they hope to have him healthy when training camp opens in late July and ready to start the season opener in September.

“I feel pretty good about it,’’ Mularkey said of Mariota’s timetable. “You have to trust the doctor’s words, and if you know Marcus like we do, we believe with the way he goes about his business he’ll be prepared. He is not going to overdo it, he has been told to be careful. And be smart about it.”

The Titans said Mariota has been rehabbing in Oregon.

Mariota, who had just been named a Pro Bowl alternate, sustained a fractured right fibula in the Titans’ 38-17 loss to Jacksonville Dec. 24.

He underwent surgery Dec. 26 in which a metal plate was implanted.

A heavily-bearded Mariota made a public appearance last week in a video presentation from Oregon to Titans’ season ticket holders.

Mularkey said, “(Players) don’t have to be back until April 17th, and that’s when Phase One starts and that’s all voluntary. (But) we know what is going on with Marcus and his rehab daily. We do a good job of staying in touch with their training staff and are made aware of everything that is logged. … We know what is going on. He is in a boot, walking around in a boot.”