The summer signing from Wycombe Wanderers has made 16 league appearances his new club this term, but only six of them have been from the start, his last coming at Nottingham Forest on November 23.
When Onyedinma has been introduced from the bench, as happened during the second half of the 2-1 win over Bristol City on Tuesday night, he has looked a threat, doing his case to earn a nod from the opening whistle no harm at all.
However, with his impact such as it is, Jones might be happy to continue holding him back until after the interval, as he said: "Everyone has a role to play, so maybe if we started Fred and give him a full 90 he would contribute, but maybe he wouldn’t then be able to do that (impact in the second half as much).
"But he always gives us something, he always comes on and gives us something, so that could be a little role at this time.
"We’ll just see and it's not that we don’t trust him to start, of course we trust him to start.
"He’s done wonderful when he starts, but we have to think about one, the freshness of the team, two, what do we need in the early stages of the game?
"Is it going to be a tight game? Are we going to need that physicality?
"And then when the game opens up, what do we need then to threaten?
"Fred comes into that category as give him time and space when the game opens up, that’s when he’s even more dangerous.”
When Onyedinma came on against the Robins after an hour in midweek, Town had just been pegged back to 1-1, Andreas Weimann levelling the scores.
The former Millwall youngster, along with fellow sub Allan Campbell, who added some real bite and energy into the midfield, helped sway the game back into Luton's favour though, Elijah Adebayo netting the winner just seven minutes later.
Onyedinma went close to a wonderful solo goal, his control just letting down at the pivotal moment, as Jones felt the pair made a real difference, continuing: "I thought the ones we brought on had a real impact.
"That was good as we asked them to be game changers and they did, they changed the direction of the game.
"I think if we hadn't made those changes, we would have given a bit more impetus to Bristol.”
Getting the victory was all-important to Jones as well, considering it was one of their rearranged matches following an enforced break over Christmas due to Covid.
He added: "We've just got to add a bit of consistency, but that’s nine points from the last 12 after the Harrogate game, so we’re pleased with that.
"We were excellent here against Bournemouth, excellent at Reading, I thought we were decent for 45 minutes at Bramall Lane and then just imploded, but for me, they’ve got the best squad in the Championship, so that can happen.
"If we were going to lose one game that was one that you can stomach.
"Then today (Tuesday) it was important, as Bristol could have gone above us, so it was important that one, we didn’t lose the game, two we got something out of it and three, the bonus is we got three points."