The rugged Serbian centre-back ended his lengthy association with the Red Devils over the summer by electing to join Inter Milan on a free transfer.
However, his time in Italy has been a disaster, with now Nerazzuri chief Roberto Mancini having bombed him out of his first XI on the back of a host of error-strewn displays.
Vidic is now available for free in January, and Van Gaal is pondering a deal to bring him back as he plots to boost his defensive options at the Theatre of Dreams.
The 33-year-old defender achieved legendary status at United for his successes in an eight year spell at Old Trafford, and is still held in high regard despite his showings towards the end of that spell having been some way from those produced in his peak.
LVG sees Vidic as a good short-term option, with a reliance on youngsters Paddy McNair and Tyler Blackett a concern for him.
Juventus and Besiktas are also keen on the Eastern European, but a return to his former stomping ground may tempt the enforcer.
United are also considering a £25m move for Everton right-back Seamus Coleman.