The MLS duo were named by Panamanian national team manager Julio Dely Valdés as part of a group of 12 players based overseas, who will join 13 players from the domestic Panamanian league already in camp.
Panama will travel to face Jamaica on March 22 before hosting Honduras at the Estadio Rommel Fernández on March 26.
According to the official Panamanian federation site, the dozen Panamanian exports are expected to join training following matches played on the weekend of March 16-17, which is Rivalry Week in MLS. D.C. United play at New York on Saturday, March 16, while FC Dallas host the Houston Dynamo on Sunday, March 17.
Sánchez and Pérez would miss out on their clubs' MLS league matches on Saturday, March 23.