[Baggies](https://www.expressandstar.com/sport/football/west-bromwich-albion/?callback=in&code=YJIYOGNLZDETMTFLYS0ZOGE0LTGXM2UTODZHNTMZYJC5OGQZ&state=f765aaea0750499bae65afa214e31ed7) boss Mason landed a top target at the end of last week by adding to his midfield in the form of the highly-rated 21-year-old from Old Trafford.
Noted for his athleticism and ability with the ball, Collyer made 13 appearances for United last senior and Mason was keen on bringing him to The Hawthorns before September 1's deadline.
"Toby's a young player, but we know we're going to need him and he's going to help us," Mason said. "I've wanted Toby for a few weeks now. He's someone that I really believe in, which is important and I have that belief in all of my players.
"But when you go on loan to somewhere, I think you need to feel like you're wanted from the club and the manager and he certainly is that.
"Hopefully we can help him because if we help him improve and grow as a player, then it's certainly going to be beneficial to us.
Manchester United loanee Toby Collyer made his Baggies debut - the 1,000th player ever to do so - with a cameo at Wrexham. (Photo by Adam Fradgley/West Bromwich Albion FC via Getty Images)
"I think there's loads of room and loads of growth to develop. That's certainly going to happen on the training pitch. The reality is the game is the best teacher.
"The more game exposure you can get, the better, especially at a young age. I'm sure and I expect that Toby knows that I believe in him, which for me is super important.
"I'm going to put a lot of energy, the same amount of energy that I've put into him as every other one of my players, to help them grow and improve."
Ex-Albion captains Jonny Evans and Darren Fletcher work within youth roles at United, the former as loans and pathways manager.
Mason added: "He's a good kid, humble, wants to work, wants to be part of it. You can feel that as soon as you speak to him.
"He wants to play football, loves football and that's super important. We want those types of people in the building who want to work and be part of something."
"On Saturday he replaced Isaac (Price) and had a bit of a higher role, but there'll be times where he'll be a bit lower and we'll be expecting and demanding different things from him. Most importantly, he's going to work hard. He's part of a group. He's part of a team and a football club that want to help him."