Cruyff believes signing the Gunners star, 24, would mean midfield stars Sergio Busquets, Andres Iniesta and Xavi can be kept fresher during the season.
The Dutchman, 64, said: "If Cesc signs there will be four players for three places, which means all of them can share out a lot of games.
"There comes a stage in the season when everything is at stake but the team is out of gas.
"As good as the Barca players are - and they are good - there comes a time where they've played too many games.
"You need players not only to strengthen competition but also to move things around without upsetting the team's rhythm."