The burly Belgian looks unlikely to return to Goodison Park next season after a successful loan stint with the Toffees, as Chelsea plot to bring him back.
Although Everton are keen to keep Lukaku, talk of a big money move or a possible future at Stamford Bridge looks set to scupper any potential agreement.
As a result, Martinez is shopping around for alternatives and has set his sights on Welbeck.
The 23-year-old England international – who is a part of Roy Hodgson’s World Cup set-up – is rumoured to be growing frustrated at his current role at Old Trafford, with his first-team status unclear.
Welbeck played infrequently under David Moyes last term, and he may be unable to hold down a berth in his favoured central role with new chief Louis van Gaal, who is known to be a huge fan of Robin van Persie.
Everton are ready to give him the platform his craves, and could push for either a loan move or a permanent transfer.
United themselves might opt to attempt to negotiate a shock swap deal involving Ross Barkley, however it is understood that the Merseysiders are unwilling to let the midfielder leave.