"The majority of the squad have been in for three days this week and they've been assessed as to where they are in terms of fitness and to see where they are going," said O'Kelly.
"They have all come in and shown wonderful enthusiasm. In fact we've had to slow some of them down and that is always pleasing.
"You don't want players to work their socks off at this time of the year, but they need to come back in decent shape when we report back for pre-season training on July 6 so that you can build on it."
Rovers play the first of five public pre-season games away to local Northern Counties East side Armthorpe Welfare two days later.
In addition to the public games, Rovers are hoping to arrange a couple of behind-closed-doors friendlies against Premier League club's Under-21 sides.
"If we could do that - there could be a problem fitting them into our schedule due to the fact that Premier League clubs don't report back until a week later than we do - then that would be a nice balance for us,"
"You have more flexibility - especially in the early part of pre-season - playing behind closed doors because you can train before or after the game so you can have a couple of sessions in the same day.
"You can also work on team shape, balance and organisation and responsibility and how the team adapts to different system - all against good quality opposition.
"When you play any game in public people always look at the result, whereas if you are playing behind closed doors the result doesn't matter."
O'Kelly confirmed that Rovers would again be spending time in a training camp during their pre-season campaign.
"We will be spending four days away prior to playing at Barrow on July 18th," he said.
"It's good to get away from the training ground - though we really like it here - because it is a different environment and you are doing different activities and it is good for team bonding."
"They have all come in and shown wonderful enthusiasm. In fact we've had to slow some of them down and that is always pleasing.
"You don't want players to work their socks off at this time of the year, but they need to come back in decent shape when we report back for pre-season training on July 6 so that you can build on it."
Rovers play the first of five public pre-season games away to local Northern Counties East side Armthorpe Welfare two days later.
In addition to the public games, Rovers are hoping to arrange a couple of behind-closed-doors friendlies against Premier League club's Under-21 sides.
"If we could do that - there could be a problem fitting them into our schedule due to the fact that Premier League clubs don't report back until a week later than we do - then that would be a nice balance for us,"
"You have more flexibility - especially in the early part of pre-season - playing behind closed doors because you can train before or after the game so you can have a couple of sessions in the same day.
"You can also work on team shape, balance and organisation and responsibility and how the team adapts to different system - all against good quality opposition.
"When you play any game in public people always look at the result, whereas if you are playing behind closed doors the result doesn't matter."
O'Kelly confirmed that Rovers would again be spending time in a training camp during their pre-season campaign.
"We will be spending four days away prior to playing at Barrow on July 18th," he said.
"It's good to get away from the training ground - though we really like it here - because it is a different environment and you are doing different activities and it is good for team bonding."