The youngster will be Paul Robinson's understudy following Nigel Martyn's departure for Everton last month.
The Cumbrian-born keeper has played twice for the reserves this season, and has impressed each time. Despite his age he is already at a stage where he will begin to challenge Robinson for his place in the first team.
Carson's progress over the past year has been rapid, and even with England international Martyn no longer at the club, Reid is confident he has an excellent bunch of goalkeepers to choose from in Robinson, Carson and Australian Olympic keeper Danny Milosevic.
"The goalkeeping situation here is very, very healthy," said Reid.
Sixteen-year-old Aaron Lennon is set to keep his place on the bench after an impressive display against Middlesbrough for United's first ever visit to the new Walkers Stadium.