Alex Stevenson and Kris Shakes were named the conference's Big Ten Offensive and Defensive Players of the Week Tuesday.
In the Nittany Lions' Penn State Invitational performance, Mruzik registered 53 kills, 14 digs, eight blocks, and three aces.
The Nittany Lions fell six spots from their previous preseason position at No. 5.
The Lady Lions begin an 11-game non-conference slate on November 7 at home against Bucknell.
After winning three matches over the weekend, the Nittany Lions climbed two spots in the AVCA national poll.
Goals from Peter Mangione and Alex Stevenson lifted the Nittany Lions over the Red Storm Monday night.