Kerriann Herdelin
Executive Director

Kerriann Herdelin joined GPTL in 2010 and has grown the National Junior Tennis & Learning from 50 players a year to approaching 2000 players yearly.  She has over 20 years of tennis experience and educational leadership. She oversees all business operations and programming, including Administration, Communication, Advancement, Community Outreach Programs, Events, grants and innovation. Kerriann earned a bachelor’s in Elementary Education, a Masters in Special Education and studied Educational Leadership. She was a Division I scholarship player at Niagara University.  Kerriann coached The Hill School tennis team connecting her with GPTL. Kerriann has three daughters that all play tennis. 


Corey Bowlin
Director of Tennis

Corey Bowlin joined GPTL in February of 2022. He has over 25 years in the tennis industry as a teaching professional, head pro and director of tennis. Most recently, Corey was at Frog Hollow Racquet Club in Lansdale for the past 11 years. While there he was a tennis professional, director of tennis and managed the pro shop. Corey also worked for a tennis management company (Peter Burwash International) where he managed all levels of tennis programs and was able to travel and teach in the Caribbean. He also was the director of tennis for 5 years at Palmas del Mar, the largest tennis facility in the Caribbean. Since living in Pennsylvania, Corey has been a volunteer coach with Special Olympics tennis and basketball. For the past school season, he has also been a volunteer coach at Upper Perk Valley for the girls and boys high school teams. Corey is looking forward to being part of the GPTL community and helping grow the great game of tennis.


Maryellen Wilson
Director of Administrative Services

Maryellen Wilson joined GPTL in 2009.  As Director of Administrative Services, she manages administrative and support operations that include bookkeeping, accounts receivable, registrations, email marketing, website content and Leagues organization.  Maryellen has over 50 years of tennis playing experience and has PTR Certifications for Adult Development and 10 and Under Tennis.  Maryellen is a graduate of the University of Delaware and played four years of Division I Varsity tennis for the Blue Hens earning MVP honors.  For several years, Maryellen coached the Pottsgrove High School Boys’ and Girls’ tennis teams. 


Andrew Wilson
Andrew Wilson has coached for GPTL since 2010.  He has PTR Certifications for 11 to 17 and 10 and Under Tennis.  Andrew is a graduate of Lebanon Valley College where he played four years of Division III Men’s Varsity tennis and was a MAC Academic Honor Roll recipient.  He has competed in USTA sanctioned junior and adult tournaments and was MVP for the Boyertown Area Senior High School Varsity tennis team.