The striker has two years left on his contract but is exasperated at a lack of consistent first-team chances up front. Welbeck was dropped for Sunday's game away at Everton, with Nani preferred to him out wide.
Spurs are keen admirers of the 23-year-old, who is almost certain to be in England's World Cup squad this summer.
A number of other top flight sides are monitoring Welbeck's situation at Old Trafford.
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