The Red Devils lost 8-7 on penalties to Championship side Derby County in the Carabao Cup third round at Old Trafford on Wednesday night.
Manchester United manager Jose Mourinho stripped Pogba of the vice captaincy ahead of the visit of Frank Lampard’s Derby team.
Pogba sparked controversy with his blunt assessment of Manchester United’s style of play in a 1-1 draw with Wolverhampton Wanderers in the Premier League last weekend.
The 25-year-old was linked with a potential move to FC Barcelona in the summer transfer window but a deal failed to materialise.
Former Arsenal star Merson delivered a withering verdict on Mourinho and Pogba ahead of their trip to West Ham on Saturday afternoon.
“It’s not working between Paul Pogba and Jose Mourinho, they don’t look happy,” Merson told Sky Sports.
“I’ve seen the video of Pogba coming onto the training pitch and Mourinho says something to him, so it isn’t good at all.
“With the results as well, it just gets blown up even more. If they had won their last two games, it wouldn’t be a problem, but they’re out of the title race and out of one of the cups already which they had a chance of winning.
“For me, it’s worrying times at Man Utd now.”
Pogba moved to Manchester United in an £89m deal from Serie A giants Juventus in the 2016 summer transfer window.
The Red Devils finished in second spot in the Premier League table last term to secure their best finish since the Sir Alex Ferguson era.
Manchester United signed Shakhtar Donetsk midfielder Fred, FC Porto defender Diogo Dalot and Stoke City goalkeeper Lee Grant.
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