Alabi is the first player in what Brian Laws and Russ Wilcox will be a successful link up between the two clubs.
The 18 year old played against the Iron in Stoke's 3-1 reserve friendly victory over them on Monday afternoon, and Brian Laws was delighted to bring in the powerful front man.
“We’d already spoken about James coming here prior to the game this week, but it was important we went to have another look at him and a chat with him as well," Laws told the Scunthorpe Telegraph.
“Monday was a golden opportunity and we’re thankful to Tony Pulis and Stoke City for supporting us and allowing the player to come.
“We were impressed with him earlier in the season when we saw him play Manchester United’s reserves. He caused them all sorts of problems.
“He’ll give us that thrust, an aerial ability whereas the majority of our strikers all want the ball to their feet.
“He can cope with it at his feet, but physically, if we put the ball over the top, he’ll cause people problems.
“At least it gives us some ammunition – a Plan B or C, whatever you want to call it.
“He’s certainly a welcome addition."
The 18-year-old forward will be at Glanford Park until after the home clash with Doncaster Rovers on Saturday, March 23.
However Brian Laws insists the move may turn out to develop into something more long term for next season, with the possibility of a season long loan on the cards.
“He’s just here for a month but it’s with a view to it being longer. Initially we’ll see how it pans out and how we’ll he settles in with us," added the United manager.
“It’s costing us nothing to do it, so financially it’s a win-win situation for us. It allows us to get an extra body into the club but there’s no pressure for us to play him."