Mark Chassay, M.D. is the former Medical Director for the ATEP. He has practiced sports and family medicine since 1995. Previously, he worked in college health at University Health Services on the campus of The University of Texas at Austin from 1996-2003. From August 1996 until January 2005, he served as Team Physician and Coordinator of Sports Medicine for Women's Athletics at the University of Texas at Austin. In February 2005, Dr. Chassay was promoted to Head Team Physician for Intercollegiate Athletics, a position he held until January 1, 2012 when he was appointed Deputy Executive Commissioner at Texas Health & Human Services. Dr. Chassay still continues his 16th season of work with UT Athletics as an Assistant Team Physician. In addition, Dr. Chassay was the Team Medical Physician for the Austin Wranglers Arena Football League franchise from its inaugural season in 2003 to 2005. He co-founded Texas Sports & Family Medicine, PLLC with Mark Hutchens, M.D. and Robyn McCarty, M.D in 2003. Dr. Chassay is also involved in the United States Olympic Committee Volunteer Program. In September 2003, he completed the United States Olympic Committee Level I Volunteer Program at the Chula Visit (California) Training Center. In May 2005, he served as Chief Medical Officer for the United States at the VISA World Paralympic Cup in Manchester, England. Dr. Chassay served as a Medical Officer at the 2007 Pan American Games in Rio de Janeiro, Brazil in July 2007 and for Team USA at the XXIX Summer Olympics held in Beijing, China in August 2008. He served as Chief Medical Officer at the November 2011 Parapan American Games in Guadalajara, Mexico. Dr. Chassay will serve in his 5th multi-sport international games this time as the Chief Medical Officer for team USA at the London Paralympic Games in August/September 2012. He served as President of the Travis County Medical Society in 2010. Outside of medicine, Dr. Chassay enjoys running, genealogy and spending time with his wife Kimberly and son Huston born in 2011.

Timothy Vachris, M.D. was born and raised in Houston, Texas. He attended St. Thomas with a B.A. in Biology and Spanish. He went on to earn his Medical degree from the University of Texas Medical School at Houston in 2005. He completed his residency in Family Medicine at Memorial Southwest Family Medicine Residency in Sugarland, Texas. While in residency, he developed an interest in Sports Medicine, and helped with the care of the athletes at the Univerity of St. Thomas.
After completing his residency in 2008, he moved to Rancho Cucamonga, California to complete a primary care sports medicine fellowship at Kaiser Permanente in Fontana, California. While in Southern California, Dr. Vachris provided sports medicine coverage at Team Physician for Claremont McKenna College, Cal State University, San Bernardino in addition to Los Osos High School.
In August 2009, he started practicing at Texas Sports & Family Medicine. Dr. Vachris has also been appointed Assistant Team Physician for Intercollegiate Athletics at the University of Texas at Austin. He will be working specifically with Women's Basketball while also providing coverage for other events.
Outside of medicine, Dr. Vachris enjoys running, watching movies, and attending concets. He recently married the former Amy Lee Ann Sonnen of Houston, Texas in June 2010.