The 17-year-old midfielder has been regularly training with the first team and was an unused substitute against Newcastle United in the Premier League last month.
Mainoo is a regular in Manchester United’s Under-21 set-up and is considered a big talent coming through the academy.
He is rated highly by the Manchester United coaches and has also played for England at youth level.
Binnion stressed that Mainoo has a good head on his shoulders and is remarkably consistent for a player of his age both on the pitch and in training.
The Manchester United academy coach also pointed out that he has played in multiple midfield positions this season, which shows his football intelligence and the progress he has been making both physically and at the technical level.
He believes that the fact that Mainoo, at 17, is a regular in the Manchester United Under-21s and England’s youth set-up shows that the midfielder is coming along nicely.
“He’s been really consistent”, Binnion told The Athletic.
“With young players, they’re up, they’re down, and sometimes they get carried away with themselves.
“Then they get a reality check and struggle to deal with it.
“The thing with Kobbie is that he comes into the club every day, he applies himself really well.
“He’s never too high, never too low. He’s got quite an old head on his shoulders.
“In recent weeks, we’ve seen him play as a 6, 8 and 10, and that shows the making of a really good football brain and an athletic capability to play throughout the pitch and play in different roles and systems.
“He’s progressing nicely.
“His strengths are close control, good awareness, body contact.
“He’s really good in both boxes, he’s combative.
“He’s got a nice blend of many skills.
“He’s been training with the first team and doing well.
“For him, at 17, to play for England, to play regularly with the under-21s and train regularly with the first team and then play games for our under-18s and excel is a great mix for a young player.”
It remains to be seen whether Mainoo gets a look in for Manchester United’s first team and makes his senior debut at some point this season.