If the Titans are looking for some last-minute draft advice, they can get plenty from a familiar face -- Jeff Fisher!!

The former Tennessee head coach sat down with TMZ Sports as the Titans prepare to make the No. 1 overall pick in Thursday's annual NFL selection party ... and he issued a few warnings to his old team.

First and foremost, Fisher said if Brian Callahan and Co. have a quarterback they love ... he said they shouldn't overthink it -- and race to the podium to select the signal-caller.

But, he also cautioned his former squad to "be careful about convincing yourself that you really, really like this player at that pick."

"You've got to be careful about getting too much information," said Fisher, who coached the Titans' franchise for nearly two decades, "and falling in love with somebody that's not the answer to your problems."

He went on to say trading down would absolutely not be the worst thing -- explaining, "You can turn the corner real quickly by acquiring high picks over the next couple years."

The Titans are widely expected to stay with their pick ... and former Univ. of Miami QB Cam Ward seems to be their choice. Colorado ATH Travis Hunter and Penn State EDGE Abdul Carter will no doubt receive consideration too.

They'll officially make their selection in Green Bay shortly after 5 PM ... and it's safe to say everyone in the NFL world -- including Fisher -- will be glued to the TV when Roger Goodell reads their pick.