And he has high hopes that the 24-year-old can emerge as a key man next season.
Ferguson, who takes his side to Gillingham tomorrow, admits he asked too much too soon of the Northern Ireland international at then end of last season when he returned from a cruciate knee ligament injury.
The defender-turned-midfielder only made his first appearance of this season in February following further problems with his knee - but has since impressed in the holding role.
And Rovers’ boss has vowed not to make the same mistake again.
“I think people forget he’s still a young boy,” said Ferguson.
“He needs to get through the season fit. He needs to maintain his fitness.
“And then we need to get a pre-season into him.
“And then you’re going to see a very good player. I rate the boy very highly, I think he’s a very good player.”
Ferguson revealed McCullough would have made way for Ben Whiteman on Easter Monday, only for the Keepmoat Stadium clash with AFC Wimbledon to fall victim to the wet weather.
“In terms of managing him it’s not so much on a day-to-day basis but certainly there was no way he would’ve played Friday and Monday,” said Ferguson.
“We made that mistake last season when I relied on him too much.
“I remember the game at Hartlepool, he should never have played and that was my mistake.
“I’ve got to make sure we keep him right and make sure he gets enough games this season, also to give him confidence.
“But he’s got to have a full pre-season with us. He’s not had one for a couple of years and it’s so important for these players.
“I’ve been very happy with Luke,” he added.
“I’ve got some good players in there: Houghton, Whiteman, McCullough, Rowe, Coppinger. They’re good players.”
Rovers are aiming to make it three straight wins this weekend.
Alex Kiwomya has returned to training following his bout of illness.