New York Red Bulls' Michael Amir Murillo didn't play in Panama's 0-0 draw with Costa Rica on June 8, and isn't necessarily expected to see a minute on the field against Honduras on June 13. But his presence (most likely) on the bench for this match and the possibility he might get some playing time is the primary reason for RBNY fans to take an interest in this game.
There are other reasons, of course. First, for RBNY fans who also support USMNT, Panama looks like the USA's chief rival for the third and final automatic qualifying spot out of CONCACAF for the 2018 World Cup.