Gabriel impressed on his first appearance for Brazil in their 5-1 World Cup qualifying win over Bolivia.
But the 25-year-old was substituted after 85 minutes and was then seen on the Brazil bench with an ice pack on his thigh.
An issue for Gabriel would be another blow for Arsenal manager Mikel Arteta, who has already lost Thomas Party and Jurrien Timber to injury.
Arsenal will hope the problem is nothing serious.
Brazil play Peru in Lima on Wednesday before Gabriel is due to return to Arsenal ahead of their return to Premier League action against Everton at Goodison Park on Sunday.
After his Brazil debut, Gabriel posted on Instagram: “Only God knows how much I’ve waited for this moment! So happy for the debut and the big win. Thank you Belem do Para for the incredible energy. Come on Brazil.”