Schweinsteiger, who spent 16 years at Bayern, moved to United earlier this summer but Guardiola stressed first and foremost the Red Devils have to get the World Cup winner back to peak condition.
“When he does not have injury problems, I am completely convinced he will do very well at Manchester United. He is a top, top player,” the Bayern boss said of the 31-year-old.
“Unfortunately, during the last three years he was never in good condition. He is going to play really well there (at United). I really hope that is going to happen.”
Guardiola, speaking at a press conference ahead of the Audi Cup, also reserved praise for rumoured United transfer target Pedro.
The 44-year-old watched the Barcelona forward develop during his time at the Nou Camp and he rates him as being among the very best.
“He (Pedro) is one of the best players you can imagine,” Guardiola added.
“He’s won the European Cup, the Champions League and played millions of games for Barcelona. He can play in any team in the world, but I don’t know the situation right now. He’s a great player.”