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. 


Chris Herdelin
Director of Education

Chris Herdelin has been appointed to a new position as Director of Education.  Chris will foster improvements in tennis, education, health, and fitness using data to track and evaluate individual performance and offer suggestions for increased productivity and overall growth and development.  He has a Bachelor of Arts in Economics from Thomas Edison State University, Bachelor of Arts in History from Eastern University and is currently a Graduate Student at Texas A&M University working on his Masters of Science in Financial Economics.  Chris has been part of GPTL from 2010 mentoring all year-round tennis programs and has an extensive tennis background.  Chris was a Director of High Performance at the Arthur Ashe Youth Tennis Center in Philadelphia, where programs focus on exposing disadvantaged youth to lifetime tennis play.  Chris’ focus for GPTL will include surveying customer experiences, optimizing pricing, grant research, and submissions, analyzing economic parameters, tracking performance metrics and applying data to implement mission focused strategies and to build partnerships.  For the after-school program, he will evaluate the performance of the participants and design the curriculum with a focus on health, fitness, education and tennis. 


Maryellen Wilson
Administrative Manager

Maryellen Wilson joined GPTL in 2009.  As Administrative Manager, she manages administrative and support operations that include bookkeeping, accounts receivable, registrations, email marketing, website content and Leagues organization.  Maryellen has over 45 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.




Mark Kauffman
Mark Kauffman has coached for GPTL since 2014 and has over 20 years of tennis playing experience.  He was an instructor at summer tennis camps in Lancaster where he developed various lesson plans for children of all skill levels.  Mark played competitively as a junior in the USTA Middle States Central Pennsylvania region where he held a top ten ranking and was the number one player and captain of his high school tennis team.  Mark is a graduate of Loyola University Maryland.



Julia Kurtz Yauneridge
Julia is a certified coach from the Professional Tennis Registry (PTR), United States Professional Tennis Association (USPTA) and is a 10 and Under tennis expert.  She played college tennis for Ursinus College and has coached tennis for the past 13 years.  Previously she was the Junior Development Coordinator at The Upper Main Line YMCA.  Julia is a Philadelphia District Gold Cup instructor and is the Head Girls Tennis Coach at Twin Valley High School.