Brazil star Neymar was withdrawn in the 51st minute of Barca's 5-0 demolition of Levante on Sunday, with Luis Enrique confirming after the game that he had sustained a left ankle injury.
The 22-year-old, who opened the scoring at Estadio Ciudad de Valencia, has been in superb form after missing Barca's opening Liga game of the campaign against Elche with a sprain to the same ankle.
And Luis Enrique now faces an anxious wait to discover whether the former Santos man - who missed training on Monday - will be fit for Wednesday's trip to La Rosaleda.
"Neymar has twisted his ankle but we don't know just yet how bad it will be. The doctors will scan it in the morning and see how it all looks," he said after the Levante game.
"When a player has something like that it's always scary at the beginning and he asked to be substituted.
"After he wanted to play on, but we had already decided to make the substitution at the break in order to make sure we didn't risk anything.
"I hope it is nothing serious and that there is nothing to worry about."
Sunday's hammering of Levante extended Luis Enrique's perfect record since taking over at Camp Nou in the close-season to five wins from five competitive fixtures, with zero goals conceded.
Lionel Messi appears re-energised after the ex-Celta Vigo boss' arrival and, ominously for Malaga, the Argentina captain has scored five goals in his last three appearances at La Rosaleda.
Indeed, Malaga has been a happy hunting ground for Barca in general in recent years, with the Catalan giants having won on each of their last seven visits to the Andalusian city in all competitions.
But as well as the likely absence of Neymar, Luis Enrique may also be without Croatian midfielder Ivan Rakitic, who did not train on Monday after sustaining bruising to his left foot at Levante.
Rafinha Alcantara (thigh) also looks set to miss out, while Thomas Vermaelen's wait for his Barca debut looks set to go on as he has not yet received medical clearance after a hamstring problem.
Malaga, meanwhile, head into Wednesday's clash on the back of a 2-2 draw with Barca's Catalan rivals Espanyol.
Javi Gracia's team required an injury-time leveller from Duda to rescue a point at Estadi Cornella-El Prat, and the Portuguese full-back was delighted to have snatched a draw.
"The important thing is that the team responded and we came away with a draw and another point," commented the 34-year-old.
"We need to keep gaining as many points as we can - the season is just getting started."
Malaga have collected five points from their four Liga fixtures so far this term, with their sole win coming against Athletic Bilbao on the opening day.
Gracia could be without Fernando Tissone, Pablo Perez and Vitorino Antunes for Barca's visit as the trio all trained away from the team on Monday, while Arthur Boka was also absent due to personal reasons.
