Rottier was named the head women's basketball coach in June of 2021. Since joining the program, he has helped the Phoenix reach heights not seen in two decades.
 
This past season he coached the Phoenix to a 16-9 overall record with a 13-5 conference mark to earn the No. 2 seed in the CSAC Championship tournament and host a playoff game. The number of wins and .640 winning percentage were the third-best marks since Wilson joined the NCAA and also the best results since the 2000-01 season. During the process he coached three All-CSAC selections, including the CSAC Rookie of the Year, and three Academic All-District choices. The season was highlighted by handing Notre Dame its only loss in conference play.
 
Rottier’s first season as the head coach saw the Phoenix go 12-14 overall and 10-8 in the CSAC. It was a seven-win improvement both overall and in conference compared to the previous season played in 2019-20 (no games were played in 2020-21 because of COVID). As a result, the Phoenix landed two student-athletes on the All-CSAC team. The team hosted a playoff game as the No. 4 seed in the CSAC Championship and advanced to the semifinals.

During his time at Elizabethtown College, Rottier helped the Blue Jays to back-to-back post-season appearances, including finishing runner-up in the Landmark Conference championship during the 2018-19 season. He was instrumental in recruiting and developing players that led the Blue Jays to a 19-7 record during the 2018-19 season and was a member of the Landmark Conference Coaching Staff of the Year for the 2018-19 season. Prior to his arrival at Elizabethtown, Rottier served as an assistant men's basketball coach at Thaddeus Stevens College where he served as the program's recruiting coordinator and offensive coordinator. The Bulldogs increased their scoring output and earned the programs first appearance in the conference championship in nine years. Rottier has also coached several AAU and high school teams in the Central Pennsylvania region.

Rottier received his bachelor's degree in business administration from California Coast University and received two master's degrees from Concordia University Irvine: one in coaching and exercise science and the other in coaching and athletic administration. In addition to his work in higher education Rottier has nearly 20 years of professional experience in the private sector including management positions for e-commerce, online marketing, sales, and operations and has held leadership positions in nine different professional and community organizations.