The French World Cup winner clashed with Mourinho during the Portuguese's time at Old Trafford, and Pogba explained last week why their relationship was damaged.
However, Keane has expressed that Pogba should be focusing on performing on the pitch, as opposed to making headlines off it.
Speaking to Sky Sports News, the Irishman said: "I think we've all discussed many times over the last few years, Paul Pogba is a talented player, absolutely, there's no getting away from that. But I still feel he hasn't done enough at Man United.
"He obviously fell out with Mourinho, that was a big problem at the club, but even the last few months, we're saying he's had a big influence, I wouldn't agree with that.
"I think he's playing ok and he's a good player, but I still look in some of the big crunch games United have had this year, he hasn't turned up.
"Not just his fault but they lost at Leicester, which was a big cup game for them, Man City at home, he didn't perform that night. So I think Paul needs a bit of a reminder why he's playing for Manchester United."
Pogba has made 35 appearances for Ole Gunnar Solskjaer's side this season, scoring five goals and providing seven assists for the team. body check tags ::