Cain spent 2019 to 2021 in Happy Valley before transferring to LSU.
Posluszny was the 26th Nittany Lion named a Hall of Famer.
One way or another, the best in Pennsylvania stay in Pennsylvania and play for Penn State.
Driver, who has three years of eligibility remaining, entered the transfer portal on December 5.
Rucci comes from Wisconsin with two years of eligibility remaining.
Mayer spent one year at Wisconsin and has no recorded appearances or statistics.