Ole Gunnar Solskjaer claims to be unruffled by the start of sacking season as the under-fire Manchester United manager prepares for predecessor Jose Mourinho's Old Trafford return.

Premier League draws with promoted Sheffield United and Aston Villa either side of the Europa League loss at Astana have ratcheted up the pressure on the 1999 treble hero.

United are in the midst of their worst start to a top-flight campaign in 31 years, having mustered just four Premier League wins ahead of Tottenham's highly-anticipated arrival on Wednesday.

Mourinho will be hoping to compound matters on his first return to the Old Trafford touchline, having benefited from the start of sacking season.

Spurs boss Mauricio Pochettino, Arsenal's Unai Emery and Watford head coach Quique Sanchez Flores have all left in the last fortnight – managerial changes that Solskjaer says have not alarmed him.

"No, it doesn't make me more concerned," the United boss said.

"I'm just focusing on my job and that's doing as well as I can and look forward to the next game, but also look long-term, plan things with board.

"It's that time of year. It's never nice to see your colleagues lose their jobs – now three in a very short space of time.

"Some of them, you can talk about this VAR all day long, and I don't know what the reasons behind the sacking at different clubs.

"But one result, for example, the Southampton v Watford one, with that handball and (if it is called) we're talking about something completely different maybe.

"It is as football is – it's a game of margins. Sometimes you have luck, sometimes you don't, but it doesn't make me any more concerned that it's December, no."

Solskjaer's side sit ninth in the Premier League on 18 points after 14 games, but there have been no "knee-jerk" conversations with executive vice-chairman Ed Woodward or the owners.

Mourinho was sacked last December with United sixth after collecting 26 points from 17 matches, having won the Europa League, EFL Cup and Community Shield before things fell apart towards the end of his tenure.

The Portuguese has received a warm welcome when returning as part of his role with Sky Sports and Solskjaer expects the Spurs boss to receive similar on Wednesday.

"Very good reception," Solskjaer said. "Of course that's just a testament to this club and the supporters of this club.

"Of course they remember the two-and-a-half years he was here, he won trophies. I'm 100 per cent sure our fans will welcome him, and the staff and the club, everyone.

"I can't remember the league position we were in (when I replaced Mourinho) but I've had now 50 games since then and the club it isn't where it should have been and isn't where we want to be and we know we have to improve.

"We are working hard to do that right and when you change manager halfway through the season it isn't where it is supposed to be."

While Mourinho can expect a warm greeting, few United players are expected to be so welcoming given the way things unravelled.

Paul Pogba clashed with Mourinho towards the end of his Old Trafford reign but the midfielder will not be back from an ankle injury that has kept him out since September.

"No. Paul's not ready, no," he said.

"He's still a bit away but he's working hard so let's see. He's out on the grass, so let's see how long it will take."

Pogba's continued absence has highlighted the midfield issues at United, so too the absence of two of Mourinho's most trusted lieutenants.

Scott McTominay's influence has been sorely missed as an ankle issue kept him out of the club's last three matches, while Nemanja Matic has not played for two months.

"They're touch and go," Solskjaer said ahead of the Spurs encounter.

"So, let's get this training session out of the way. We've got more games than this one, so of course I can't look at just the one game, we have got to look at long term."