Gunners' Spanish skipper would make the current European champions even more powerful than they currently are, according to the club's Dutch legend
The former player and coach at Camp Nou has urged Pep Guardiola to get his chequebook out and use the bulk of his budget to add the 24-year-old to Barcelona's already-talented squad.
Cruyff is convinced Barca need more depth to their squad but the European champions will face a stiff challenge yet again, with Arsene Wenger still keen to keep the midfielder.
The 64-year-old said to The Sun: "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."
Barcelona secured their second Champions League victory in three years by beating Manchester United at Wembley in May and Cruyff insists adding to squad depth is very important ahead of next season.
He added: "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 too much."