The 27-year-old has fallen out of favour with Pep Guardiola, after being openly criticised for a lack of enthusiasm in training, resulting in his omission from last night's squad for the 2-0 victory over Borussia Monchengladbach.
Red Devils boss David Moyes was in attendance for Friday's Bundesliga clash, hoping to run the rule over the Croatia international, ahead of a proposed bid to bring him to Old Trafford, according to the Daily Mail.
He will be heartened to hear of Mandzukic's fall down the first-team pecking order at the Allianz Arena, but not so much that the Gunners are plotting a rival bid of their own.
Arsene Wenger is keen to add a new striker to his Emirates Stadium squad, in an attempt to strengthen Arsenal's Premier League title push, and might be inclined to make an offer to take him on loan for the rest of the season.
Mandzukic remains under contract with Bayern Munich until 2016, but there have been suggestions that Guardiola is ready to part with the prolific marksman, even before the arrival of Robert Lewandowski this summer.
"Mandzukic could pack his bags," admitted club legend Franz Beckenbauer. "I see Lewandowski in the attack, his playing style is suited for [Pep] Guardiola's ideas than that of Manduzkic.
"There are even more reasons why he could leave - even without him, Guardiola could still count on Thomas Muller and Mario Gotze in attack."