Upon club legend Alejandro González Rojas's retirement in September 1990, then-sixteen years old Álvaro Mesén was called upon to the Alajuelense senior team to backfill the third-choice goalkeeper position, behind the more experienced pair of Desiderio Calvo and Paul Mayorga; however upon the signing of former Herediano goalkeeper José Alexis Rojas in early 1991, Mesén was sent back to the youth teams. Rojas's signing had the purpose of adding experience to Alajuelense's door, which was lacking upon González's retirement as Mayorga and Calvo only started a handful of games in the past two seasons, and neither one of them could keep the other's faults in check.