The 24-year-old, who came through the ranks at Atletico Madrid, had an operation on his left arm after breaking a bone in a freak training ground accident at the La Liga club in July.
Baston, who scored 18 goals while on loan at Eibar in the Spanish top flight last season, also sustained a thigh injury according to media reports.
"He is working, but he has to go slow (in training) for two or three days. He does not have an injury. I hope to have him available for the bench on Sunday, but I don't know. I am not sure at the moment," Guidolin told reporters.
"He worked with us last week but he needs some days where he works slowly. He is almost ready to play."
Swansea, who finished 12th in the Premier League last season, have three points from their first three games.
(Reporting by Ian Rodricks in Bengaluru; Editing by Toby Davis)
