Milan striker Pato returns from USA in time to face Barcelona
Pato, 22, picked up a thigh injury in February and has been in the USA receiving treatment, but coach Massimiliano Allegri believes that he can be fit to play on Tuesday.
"Pato should be back tomorrow [Saturday] and is in good condition," Allegri said. "We will evaluate him to see if he will be available."
The Rossoneri face Catania on the weekend and with unbeaten Juventus pushing them hard for the Serie A crown, Milan cannot afford to rest players ahead of the European clash.
"Before the quarter-final [first-leg] no-one gave us a chance, but we got a positive result and now we have to show our competitiveness to go to Catania and then prepare for the game against Barca. The team is good and we must be confident."
Pato has had a poor 2011/12 campaign, having only scored once in eleven Serie A games. Blighted by injuries, the striker will hope to get back on-track next season.