McMiller scored double-digit points in her final 13 games with the Scarlet Knights.
Penn State finishes the season with a 9-3 record.
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.