In a video posted to his Twitter account, Lukaku revealed speed scores from one of United’s pre-season training sessions in Perth last month.
Lukaku clocks in as the second-fastest member of the group at 36.43kmph, only slightly short of Diogo Dalot’s 36.46kmph, and sarcastically captioned the video: “Lack of pace”.
Shaw and Mata both wrote light-hearted responses to Lukaku, but United manager Ole Gunnar Solskjaer may not see the funny side of leaking training data.
Lukaku has not travelled with the United squad to Cardiff for Saturday’s friendly with Milan, having played no part in his club’s pre-season so far.
The Belgian is hopeful of leaving United for Italy’s Serie A, with Juventus and Internazionale both interested in his services.
Lukaku has already agreed a move to Juventus, though his departure hinges on whether Paulo Dybala is willing to move in the opposite direction.
Inter hold a long-standing interest in Lukaku but are yet to submit an acceptable offer for the Belgian, having seen a £54m bid rejected last month.
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