Locker went down with a hip injury in the first quarter of Sunday's 38-13 Titans victory over the New York Jets after completing 18-of-24 passes for 149 yards and three touchdowns.
Munchak said the signal-caller is definitely out of the Titans' upcoming contest against the unbeaten Kansas City Chiefs but added the injury wasn't a season-ending one.
"From what we've seen so far, we don't think he's lost for the season. We know that he's going to be back playing again this year, we just don't know when," he said.
Locker, he added, will undergo further tests before a definitive return date is determined.
"He still has swelling so they don't want to speculate," the coach said. "He'll be MRI'd again tomorrow, and then we'll make a time frame."
Locker also suffered a minor knee injury on the play, in which he was sacked by Jets defensive lineman Muhammad Wilkerson.
In the meantime, Ryan Fitzpatrick will take over behind center. He tossed a touchdown and threw for 108 yards after replacing Locker last week.
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