The 33-year-old former Croatia international has not had a look-in at the Italian champions under Maurizio Sarri this season, failing to play a part in any of their games so far.
Mandzukic was excluded from Juventus’ Champions League squad as it became apparently clear that his services were no longer needed at the Allianz Arena.
Sarri has opted for Cristiano Ronaldo, Paulo Dybala and Gonzalo Higuain as his main attacking options with Juventus enjoying an unbeaten start to the Serie A season.
Mandzukic, who earns £300,000 a week in Turin, was on the cusp of a move to Old Trafford in the off season but his wage demands served as an obstacle to a deal being done.
The former Bayern Munich and Atletico Madrid striker is however ready to slash his weekly wage in half in order to join the 20-time English champions in the January transfer window.
Manchester United manager Ole Gunnar Solskjaer is keen to reinforce his forward line as goals have come at a premium for the Red Devils in their opening games of the 2019/2020 season.
Manchester United let go of Romelu Lukaku, who was their top scorer for the past two seasons, and Alexis Sanchez to Inter Milan in the summer without replacing them.
The likes of Inaki Williams, Paulo Dybala and Jadon Sancho were all linked with moves to Old Trafford in the summer but the only attacking reinforcement the club made was the £15m signing of Daniel James from championship side Swansea City.
Manchester United are 14th on the Premier League table with only two wins from nine games.
