England Under-21 international Welbeck has made 18 league appearances for Sunderland, scoring five goals, despite being in competition with expensive recruits Darren Bent and Asamoah Gyan for a place in the Black Cats' strike force.
"I had a chat with Federico and explained the Welbeck situation," said Ferguson.
"It can pan out exactly the same for him. It would be the same thing, going to a club, getting that experience for six months and coming back to us a better player."
However, the success of summer signing Javier Hernandez and the return to fitness of Michael Owen look set to limit Macheda's chances up front for Manchester United.
Ferguson has concentrated his spending on the summer break in recent years and did not sign any players in January 2010.
He did sign two players in the January window the year before but Serbian winger Zoran Tosic left for CSKA Moscow in June after five first-team appearances while Belgian defender Richie de Laet only returned from a loan spell with Preston on Thursday.
Title is in Man Utd's hands - Kidd
De Laet and forward Joshua King's loans at Deepdale were due to expire after the match against Crystal Palace on 3 January, but they have returned to Old Trafford early in the wake of Ferguson's son, Darren, being sacked as Preston manager.
United agreed a deal for Danish goalkeeper Anders Lindegaard with Aalesund in November and the 26-year-old will be available for selection from January.
Ferguson conceded that he may have to reinforce his squad by recalling midfielder Tom Cleverley from his loan spell with Wigan.
Cleverley has been away from Old Trafford for almost two years, impressing on loan spells at Leicester and Watford before taking up the option of a temporary spell at the DW Stadium.
"Tom has done excellently as well but the agreement with him was always that we would review it in January," said Ferguson.
"I have a fantastic relationship with Wigan so I have not discussed it any further than that.
"The only problem is that we have lost Park Ji-sung to the Asia Cup for the whole of January and I don't have Antonio Valencia back until the end of February, so we are a bit light in that respect in terms of wide positions."
Ferguson expects Paul Scholes to return to training next week in a further boost to his midfield options.
The 35-year-old has not played since injuring his groin in the Champions League win over Rangers on 24 November.
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