Washington played at Penn State from 2014-2017.
While the Mets have not announced whether Hagenman will get the start or relieve the starter, he is the only fully rested pitcher available on the roster.
Penn State lost to Pitt for the first time dating back to the 2019 season.
The Battle of the Keystone State against Pitt is set for 5:30 p.m. on Tuesday.
The Nittany Lions hit two grand slams in the series.
Penn States heads into the Frozen Four matchup as the underdog for the third consecutive game.