Jimmy Garoppolo likely wouldn't get his job back in the playoffs if Steve Mariucci was in charge of the Niners ... the ex-head coach tells TMZ Sports he'd stay with Brock Purdy in the postseason in order to "ride the hot hand."
Garoppolo broke his foot back on Dec. 4 -- but with a recovery timetable of 7-8 weeks ... there's a chance he could be ready in time for the NFC Championship Game, or even the Super Bowl.
Mooch, though, said out at LAX last week that if SF gets that far -- and Purdy is still playing well -- he'd keep Jimmy G on the bench.
Purdy has been dominant in his 2-plus games as Garoppolo's fill-in, logging 612 passing yards, 6 passing TDs and a single INT since taking over for Jimmy G.
Mariucci clearly believes it hasn't been a fluke run ... telling us the Niners are one of the two teams that he thinks could represent the NFC in this year's Super Bowl -- even with Purdy under center.