Saint-Maximin – who has been sidelined with a hamstring injury since – celebrated the birth of his third child this week.
The winger, signed from Nice this summer, then returned to training ahead of this afternoon’s home game against Brighton and Hove Albion.
Saint-Maximin – who posted a video on Instagram this week of his two children giving money to a homeless man – had suffered a recurrence of his injury on his comeback against Tottenham Hotspur late last month.
“You're always disappointed when it's a recurrence,” said head coach Bruce. “But he's all about pace and power. Even then, he trained all week.
“The difficulty is in the summer we have six weeks. We have six weeks to get them fit, and then probably about five games. You don't have that in a season, and it's difficult to replicate.
“So what we've done is we've given him to Christian (Fernandez, United’s rehabilitation conditioning coach). He's now been with him for the best part of 10 days.
“It's been interrupted, because his third child arrived on the Monday, so he's missed a couple of days to be with the birth of his son.
“We've just specifically given him to Christian, whose had him now for 10 days and got him in the nick he's in. That will continue as well. His basic fitness levels are the ones we've worked on. I've not been able to do anything, because he's not done much for six, seven weeks.”