Rovers suffered an agonising penalty shootout defeat in their semi-final with Charlton Athletic on Friday night.
And immediately afterwards McCann declared his squad will be better placed for an improved finish next term.
“The squad will be stronger, let me tell you that,” McCann said.
“The players that are coming in to this group, this group will be stronger.
“We’re quite down the line with a few that we want to bring in.”
It is understood contract offers have been lodged with several free agents including one player who has been a regular in the Championship during the 2018/19 campaign.
It is also understood Andy Butler, Tommy Rowe, Danny Andrew and Marko Marosi have all been offered fresh terms with a decision to be made on Alfie Beestin’s future following confirmation Rovers will remain in League One.
McCann will begin the process of meeting with his existing players early this week to inform them of his plans for the coming season.
McCann said: “They’ll all be in this week.
“I’ll have some individual meetings with them all and my staff.
“It’ll be a bit of an appraisal and then they’ll be off for their holidays.
“They’ve deserved the break. They need to go an rest for two or three weeks, take their wives and families away on holiday.
“There’s some things to be finalised but over the next few days the retained and released list will go out with those who we’ve offered new contracts to and the ones we’re going to release.
“Then we’ll get on with the recruitment side of it.”
It is expected that Liam Mandeville, Tyler Garratt and Luke McCullough – all of whom have spent the season out on loan – will be released at the end of their deals this summer.