Inter Milan are keen to sign Lukaku and are understood to have seen a 60 million euros (£54million) offer rebuffed last month, while a swap deal with Juventus had been on the cards until Paulo Dybala’s prohibitive wage demands put paid to that.

While PA understands a move to Serie A remains on the cards, eyebrows were raised on Monday when the striker was pictured training with boyhood club Anderlecht.

United’s players had a day off on Monday and it was reported that Lukaku was expected back on Tuesday with the rest of Ole Gunnar Solskjaer’s squad.

However, Belgian newspaper Het Laatste Nieuws has published a photo of the striker training with Anderlecht once again on Tuesday – a matter United declined to comment on when contacted by PA.

Lukaku joined the Old Trafford giants on their pre-season tour of Australia and Asia but failed to feature in any of their four matches due to knocks.

The 26-year-old was also absent in the friendlies against Kristiansund and AC Milan upon returning to Europe.

Lukaku got under manager Solskjaer’s skin last week when posting on Twitter a video showing internal data of United players’ maximum speed in training. The message was swiftly deleted.

Asked about that following the AC Milan friendly, Solskjaer said: “I’ve spoken to Rom, yeah, to put it that way. And that’s case closed.”