The Scottish Premier League title winners rested Joe Ledley, Efe Ambrose and Kelvin Wilson for last week's defeat at motherwell, while Kris Commons was also rested to recover from an ankle knock.
This week, Georgios Samaras, Charlie Mulgrew, Gary Hooper, Fraser Forster and Emilio Izaguirre will all definitely miss the trip to Dingwall for the game with Ross County.
Mjallby insists the rest time is important for the players who have played over 50 competitive games this season, and also because Celtic have to play Champions League qualifiers in July.
"Obviously we know we have the crucial cup final which is the most important game but we still have to keep that winning mentality whoever we pick and have confidence going into the final," Mjallby said.
"It is not as if we are dismissing the other teams but with having the title in the bag, we have this luxury to pick and choose who we are going to play.
"We had the chance over the last few weeks to give some key players some time off because it is going to be a record-early return next season.
"We have to be clever. A lot of our players have played a lot of football this season. The break has been good for Joe Ledley, Kris Commons, Efe Ambrose and Kelvin Wilson.
"I know training is different to games but they all looked very fresh. Kris was back in training today and he was a stand-out. I think this break has given them a lot of energy, especially mentally."