French World Cup winner Pogba started alongside Bruno Fernandes, Fred and Scott McTominay in a midfield diamond at Old Trafford on Sunday.
The 27-year-old failed to make much of an impact before gifting Arsenal a penalty when he brought down Hector Bellerin in the second half.
Pierre-Emerick Aubameyang slotted home the spot-kick and his goal was enough to secure the three points for Mikel Arteta’s side.
It was another frustrating afternoon for Manchester United, who have now lost half of their Premier League matches this season and are 15th in the table.
Chelsea hero Leboeuf singled out Pogba for criticism after Manchester United’s latest defeat and said his ‘best position’ may be on the bench.
‘I don’t know if there is any explanation [for United’s form],’ he told ESPN. ‘It was a random win against Leipzig and a lucky one.
‘What we have seen in the Premier League is not good enough from Manchester United. The level drops dramatically.
‘It was very strange to see that diamond midfield because Ole Gunnar Solskjaer wanted Pogba in the middle of the park where he is clearly a problem because he changed him in the second half, putting him on the left wing almost.
‘He doesn’t know what to do with Pogba. Solskjaer has to rethink his position, maybe the best position for Pogba right now is the bench.
‘It seems to be a real problem. He’s causing problems in the middle of the park where he doesn’t defend. He’s like a double with [Bruno] Fernandes so it’s a real problem.
‘You cannot count on him to defend and to even have a tactic. You have to let him be free and have tactics for the others players.’
Manchester United continue their Champions League campaign on Wednesday night with a trip to Turkey to face Istanbul Basaksehir.