Pedri went off hurt in the second half of the 4-2 win at Slavia Prague in the Champions League on Wednesday.
"Tests taken this morning have confirmed that first team player Pedri has a muscular injury in his right hamstring," said Barca in a statement.
"The recovery time will be one month."
The 23-year-old Spain international will miss Barcelona's final European league phase match against Copenhagen next week, as well as LaLiga games against Real Oviedo, Elche, Girona and Mallorca.
Should Barca beat second-tier Albacete in the Copa del Rey on February 3rd, Pedri would also be out for the first leg of the semi-finals the following week.