The Argentine has been ruled out of the Catalans' trip to Andalucia after picking up a thigh injury as the Blaugrana drew 1-1 with Atletico Madrid on Wednesday. Brazil star Neymar is likely to deputise.
|8/1||Malaga are 8/1 with Bet365 to beat Barcelona
However, despite the fact Malaga will be helped by Messi's absence - the forward who scored 46 times in 32 La Liga games last year - Schuster expressed his disappointment that one of the world's top players will not be playing.
"I am someone who likes to see stars on the pitch," the 53-year-old German told Marca.
"I would have liked to see Messi here. No doubt he is a key player for Barcelona, but he is also very talented.
"It will be a game where we will demand the maximum from our team. I have really wanted to see the team against Barcelona. You have to be brave and do the right thing. We have to take advantage of our home crowd. The start will be very important."
Schuster replaced Manuel Pellegrini as Malaga coach this summer and stressed he is relishing playing Barcelona, a team he had a 100 per cent win record against whilst Real Madrid boss, including a 4-1 victory at the end of the 2007-08 Liga season en route to the title."I'm very confident, we must be positive," he continued.
"We have seen so many things in football so whatever happens it would not be a surprise. You have to try everything. I won matches against Barcelona. You have to do certain things, work hard and of course a bit of luck really helps. Let's see if we can find it."
Sunday's game is Malaga's first home fixture of La Liga season after opening their campaign with a 1-0 loss away to Valencia.