World Cup winner Fabregas was a youth player at Barca before moving to the Premier League club in September 2003 and the player has made it clear he wants to return to the Catalan capital.
GEAR:Get a Fabregas shirt
Local media reported on Monday that Barca's new president, Sandro Rosell, would travel to London this week to try to strike a deal but Guardiola was downbeat about the chances of success.
"I think that getting Cesc will cost a lot," Guardiola told a news conference at the club's training ground on the outskirts of the city.
"He is an important player for Arsenal," he added. "We want him to come but if Arsenal don't want to negotiate he won't."
Ten of Barca's first-team squad began pre-season training on Monday, with internationals including Andres Iniesta, Villa, Xavi, Lionel Messi and Gerard Pique still on holiday.
