United have been linked with more than 70 players since the close of play in the Championship season, and there's no doubt the coming months will throw up many more as the manager eyes a complete squad overhaul.
Here's the latest links to surface today...
Old target resurfaces
Newcastle are rumoured to have enquired about Valencia central defender Aymen Abdennour, according to Foot Mercato.
United tried to sign the Tunisian when he signed at the Mestalla, but were priced out of the £22million move.
Abdennour is supposedly now available for around £13m, but Everton and Marseille are likely to rival the Magpies for his signature.
Smalling an alternative option?
One player who Rafa could turn to is Chris Smalling, who is likely to be made available for transfer by Jose Mourinho.
Having nabbed Victor Lindelhof from Benfica for £30m+, Mourinho is keen to clear the decks at the back and Smalling is almost certain to be one of the first to leave, according to the Independent.
The England international has slipped down the pecking order at Old Trafford of late and Newcastle along with Everton and West Ham are said to be interested.
His substantial wages, thought to total close to £100,000 per week could prove a stumbling block, though.
Smalling has two years left on his deal with the Red Devils.
Anfield reunion at St James's Park
Rafa Benitez could be in line for a reunion with Liverpool midfielder Lucas Leiva.
The Brazilian midfielder was signed by Benitez for the Reds back in 2007, but has slipped down the pecking order at Anfield under Jurgen Klopp.
And reports in the Northern Echo today claimed Newcastle could look to sign the 30-year-old this summer.
So far, the only signing made by Newcastle has been to make Christian Atsu's loan deal permanent in a £6.2million transfer from Chelsea.
Abraham could go Dutch
Dutch newspaper De Telegraaf are reporting that Vitesse Arnhem could muscle in on Newcastle and Brighton's attempts to sign Tammy Abraham on loan from Chelsea.
Vitesse have a partnership with the Blues and have taken a number of youngsters from Stamford Bridge in recent years.
Vitesse general director Joost de Wit has been quoted by the publication on the matter. He said: "With Chelsea we are working together with great pleasure, we have announced our wishes and are fully conversant."
Interestingly, Swansea City could also firm up their interest in the England youth international, who scored 26 goals on loan at Bristol City last season.
Magpies miss out on Mooy
Huddersfield look nailed on to sign loan man Aaron Mooy for £10m.
The Manchester City midfielder was a target of United in January but no deal came to fruition.
He now looks certain to sign on the dotted line at the John Smiths Stadium, having enjoyed promotion to the Premier League with the Terriers last season.