The talented stopper has been linked with a loan move to Aston Villa.
They reported that Villa had been in contact with United over a potential loan deal until the end of the season.
Preston's Sam Johnstone
There is no doubt that Villa need another goalkeeper. Pierluigi Gollini, a summer signing from Hellas Verona, has not impressed at the club. Mark Bunn is also not universally popular, Jed Steer is injured and Matija Sarkic is only young.
Johnstone is a cheap and impressive option.
He also has plenty of Championship experience, spending time on loan in the past at Preston North End and Doncaster Rovers.
Aston Villa's Pierluigi Gollini looks dejected after Huddersfield's first goal
The 23-year-old has not played a competitive game at senior level since January and rustiness is not something Villa can afford from their goalkeeper.
His signing would also seriously undermine the summer recruit Gollini.
Johnstone recently signed a new deal at Manchester United as well so the chances of this being long-term seems slim.
New Aston Villa manager Steve Bruce during the press conference
Villa need a new goalkeeper and in Johnstone they would have a very talented and reliable stopper at this level.
On a loan deal he would be an affordable and impressive option, which Villa must act on.