It was a substiution that Jack Ross had been eager to make for a while.
Though his senior game time had been reduced from the heady days of early season, Bali Mumba continued to impress his manager and was part of numerous matchday squads.
Ross had planned to reintroduce him but the moment was never quite right.
At Plymouth he finally saw the chance and Mumba was able to get another composed senior showing under his belt.
It came just days a day after he put pen to paper on his first professional contract.
Links to Chelsea and Manchester City followed but Ross believes the 17-year-old knows he is on to a good thing with Sunderland.
International duty will prevent him appearing in the Checkatrade Trophy on Tuesday, a source of real frustration for Ross, but he could feature at Port Vale on Sunday afternoon.
"It's been a difficult balance, he's been involved with me so much but we have to be aware of his game time," Ross said.
"So a week or two ago he played for the U23s and then the U18s.
"That was to bump up his minutes because you don't want to hinder his development in that sense. But you can see that he's coming on really, really well.
"I was so pleased to get him on the pitch against Plymouth, with stoppage time it was about 10, 12 minutes he was on the pitch.
"I hope that shows how much trust I have in him that I would put him in that kind of situation.
"He's been called up for England U18s, everyone has their own opinions it, which means he'll miss Tuesday's game, and that would have been an opportunity for him to start a match," Ross added.
"Signing his contract is a good reflection I think on the club and the people that have worked with him.
"He's a good character anyway and I think he's more than happy to stay here.
"I don't think he's in a desperate rush to leave at any point."
Having sanctioned loan moves for a number of Sunderland's exciting talent since taking the Black Cats job, Ross is eager to ensure that Mumba gets senior football but he does not, at this stage at least, expect that to happen in January.
In the short to medium term Mumba looks set to keep working with the first team, topping up his competitive minutes in the club;s youth sides.
"If it was another year down the line and he was in this position I think it would be more straightforward," Ross said.
"He's still very young and at the moment it may be that a season dropping into the U23s and U18s sometimes but training every day with us is the best way to building up for next season where he would need to be playing more regularly.
"I don't want players getting to 20, 21 and they've not played first team football, I've said that before.
"This season I don't see much changing in that respect, we might reassess that in January but beyond that it would be something we look at."