Such was the levels of hard work put in by the squad in their first few days back at Cantley Park, Wellens confessed missing out planned sections of the punishing fitness work.
But he remains convinced the players will reach the level of fitness he demands in order to implement his high energy style of play come the start of the season.
“There’s been a couple of times where they’ve put that much effort in that I’ve actually let them off of some extra running at the end,” he told the Free Press.
“We don’t want to be reactive. We don’t want to say ‘we’ll get fit’ and then in four or five weeks not be quite there.
“We want to get as fit as possible as early as possible and if we need to pull the reins back with two and a half weeks to go, then we’ll pull them back.
“At least we’d know then that we could get back up to those levels.
“It’s about getting up to a level.
“We spoke to Ben Close after the first three days and he said it’s already the hardest pre-season he’s ever had.
“Because we worked really hard on the first two days, I actually let them have just a football session on Wednesday.
“You get people who have experienced different pre-seasons but there’s no easy way around it. It’s hard work. We don’t just run them around the pitch, it’s all football related, checking certain things like concentration with the ball, runners off you.
“If we can get that and not be reactive in four or five weeks, and get the mental fitness as well the physical fitness, it’ll stand us in good stead.”
It will be more of the same for the Rovers squad from Monday as they build up to the first friendly at Rossington Main next Saturday.
Wellens is seeking to condition his players so that his style of play becomes natural to them - and has warned the punishing training methods may lead to injuries in the early weeks of pre-season.
“The way I work in pre-season, we might pick up some injuries because of the way I train,” he said.
“It’s a question of whether we train them hard and risk injuries, or train them less and there’s no risk of injury but you don’t get them to the fitness levels you want to see on a Saturday.
“I feel that if you train every single day in the way that you want to play, when you come to Saturday it’s not a shock to the system. The body is in line with what is expected.
“We might pick up a few injuries along the way and we’ll try our best to manage that, which is why we’ve given them the weekend off.
“Monday, Tuesday, Wednesday we’ll do a three day block which will be hard. We’ll have Thursday off and Friday will be game related because we’re playing Rossington on the Saturday.”
While footballs will be involved at every stage, fitness is the priority for Wellens in the early weeks as he continues to get to know the group and the strengths of the individual players at his disposal.
“At the moment, in terms of tactical work, I don’t want to coach them yet,” he said.
“I want to see their natural movement and what they do. When you coach them too early sometimes, you can’t see it and you can take away a lot of their strengths.
“I want to see relationships develop over the next couple of weeks, see what natural movements they make and then we’ll coach accordingly.
“If we see them doing things naturally that we like, then we’ll take that forward and then integrate a lot of the stuff we want to do.”
Overall, the Rovers boss has been particularly pleased with what he has seen so far from his group.
He said: “Omar Bogle has been brilliant. John Bostock has been brilliant.
“Obviously Tom Anderson works at his maximum every single training session. Tommy Rowe has come in and set examples.
“I have to say they’ve all been brilliant.”