REPORTS this morning have suggested that Celtic are plotting a £1million switch for Philadelphia Union defender Mark McKenzie.

The USA international, 21, won his first cap for his country five months ago and has 18 months remaining on his MLS deal.

Celtic are looking to replace the departed Jozo Simunovic and Kristoffer Ajer has also been linked with a big money move away from Parkhead.

The Daily Mail now report that Neil Lennon's side are keeping a close eye on McKenzie as the Hoops look to bolster their defensive options.

We told yesterday how AC Milan are reportedly plotting a summer swoop for Kristoffer Ajer as part of a £75million spending spree.

The Italian giants this week appointed Ralf Rangnick as their new manager and the German will be given significant spending money ahead of the new season to strengthen his squad.

The Norwegian still has two years left on his Parkhead deal so it is understood that Milan would have to offer over £20million to have any chance of signing the defender.

Ronny Deila brought Ajer to Celtic for just £650,000 in 2016 when he joined from Norwegian side IK Start.

He then went on-loan to Kilmarnock before becoming a regular under Brendan Rodgers.