Barca drew with arch rivals Real Madrid 2-2 in Sunday night's first leg, but could have an extra face in their squad for return game after confirming Fabregas deal
The Arsenal midfielder is on the verge of returning to his former side, with both clubs confirming on Sunday evening that a deal had been made to return Fabregas to his home town.
The Spanish star will undergo a medical on Monday, and Guardiola did not rule out the possibility of the midfielder playing in the second leg, after Sunday night's first leg 2-2 draw at the Bernabeu.
"Tomorrow [Monday], we will present him and then we will see if he plays on Wednesday," Guardiola said after the match.
Goals from Lionel Messi and David Villa had put the La Liga champions into the lead but a late Xabi Alonso goal left the tie level.
Guardiola praised his men for securing such an important draw despite often being under pressure from their opponents, something he attributed to the better physical condition of Jose Mourinho's squad.
"We managed a feat and our head managed to cope with our fatigue, this was a good result," he added.
"By Wednesday, we will continue without delay [in our preparations] to compete against Madrid and I hope our fans will help us get where our legs will not be able to."
The 2-2 draw at Madrid marked Guardiola's 184th consecutive match in charge of Barcelona in which the Catalan club have more possession of the ball than their opponent.
Questioned by Goal.com's Michel Nasrallah, who attended the post-match press conference, about this record, Guardiola said: "As long as I coach Barcelona, we will keep [playing] this style, surely Real Madrid can win, but not this time."