File: Manchester United's Armenian midfielder Henrikh Mkhitaryan (L) and Arsenal's Chilean striker Alexis Sanchez.
LONDON - Alexis Sanchez is reportedly set to become a Manchester United player on Monday after a leaked image apparently showed the Chile international on the Old Trafford pitch in the club&39;s famous red shirt.
The Arsenal forward was pictured on Sunday arriving at United&39;s Carrington training complex ahead of his widely anticipated move, which will see midfielder Henrikh Mkhitaryan heading in the opposition direction.
Earlier Sunday, Sanchez posted a video on Instagram showing him walking across an airstrip towards a private jet.
A picture that was posted on social media on Sunday evening appeared to show him taking a selfie in a United shirt with his name and No. 7 on the back -- the shirt worn by club legends George Best, Eric Cantona and Cristiano Ronaldo.
Sanchez, 29, is set to become United&39;s best-paid player, with his wages estimated at more than £500,000 (R8.3-million) a week.
Arsenal boss Arsene Wenger and United manager Jose Mourinho both said they expected the two-way deal between the Premier League rivals to go through.
Wenger said Sanchez was absent from the Arsenal squad on Saturday because he was close to completing a deal that has been in the making since United out-bid Manchester City for the former Barcelona star.
"I expect soon or never," Mourinho said after his side&39;s 1-0 win against Burnley. "I think it is so close, so close, so close that if it doesn&39;t happen it&39;s not going to happen."
Former England captain Alan Shearer said City could rue missing out on Sanchez.
"City seem very blase about it," he said in his column in Britain&39;s Sun newspaper. "And given the 12-point cushion they have at the top of the Premier League why shouldn&39;t they be?
"Yes, it would have been difficult to find a regular place for him in the team given the players at Pep Guardiola&39;s disposal. But the deal is a big boost for their closest rivals.
"A club that is not content with a top-four spot and Champions League football but one who is after City and will not give up until they are back challenging for the top spot."
United -- without a Premier League title since 2013 -- are second in the Premier League and are desperate to close the gap on their fierce rivals.
Sanchez will join a powerful array of attackers including Romelu Lukaku, Marcus Rashford, Anthony Martial, Jesse Lingard and Zlatan Ibrahimovic but is expected to become a fixture in the team.
The departing Mkhitaryan struggled to pin down a permanent place under Mourinho at Old Trafford and will hope a move to Arsenal will revitalise his reputation, forged while playing for Borussia Dortmund.