Answer
Matić commonly wore the number 31 shirt during his time at Manchester United. This squad number was previously worn by Bastian Schweinsteiger, another renowned midfielder. Matić's choice of the number 31 jersey may have been influenced by his admiration for Schweinsteiger or simply a personal preference. Regardless, the number 31 jersey became synonymous with Matić's presence on the field, solidifying his identity as a key player for Manchester United.