Athletic Trainer Bios
Chicago Cubs
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Director of Athletic Training

Mark O'Neal

Mark joined the Chicago Cubs in 2004 as Head Athletic Trainer and was promoted to his present role as Director of Medical Administration’s in October of 2012. Having spent his previous 15 seasons in the St. Louis Cardinals’ organization, Mark joined the Cardinals major league staff in 1998 as the medical and rehabilitation coordinator and was promoted to assistant athletic trainer in 2003. En route to the major leagues, Mark made stops in the Cardinals’ farm system at Savannah (A), Arkansas (AA) and Louisville (AAA). He is a Certified Member of NATA, a licensed athletic trainer in the states of Illinois, Arizona and Missouri, a member of the Missouri Board of Healing Arts and a member of the NSCA. Mark had the honor of working the 2009 All-Star game in St. Louis. In 2008 Mark joined Cubs’ Assistant Athletic Trainer Ed Halbur in being named the 2008 Major League Athletic Training Staff of the Year, and in 2007 Mark was elected Secretary of the Professional Baseball Athletic Trainer’s Society’s Executive Board. He was a keynote speaker on the Kinetic Chain Assessment at the 2003 NATA National Convention and a speaker at the Annual Medical and Legal Controversies in Sports Conference at Northwestern University. In December of 2013, Mark was unanimously elected by its membership to be President of PBATS. In his first year in that position Mark reinvigorated tobacco education in baseball and established ProTep, the Professional Tobacco Education Program. In addition, Mark solidified the ATC program, a program designed to involve young people with disabilities in mainstream baseball programs. Mark also works with MLB and USA Baseball on instructions and injury prevention programs for young people. A graduate of the University of Arkansas, he worked for the football and basketball teams while an undergraduate and graduate assistant. Mark has a private pilot’s license and enjoys flying with his sons. Mark and his wife, Stefanie, reside in Chicago, Ill., with their three children (Conner, Cade and Kyle).

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Head Athletic Trainer

PJ Mainville

PJ begins his sixth season as the head athletic trainer for the Chicago Cubs. Prior to joining the Cubs, he completed the previous two seasons (2011-2012) as the Assistant Athletic Trainer for the Arizona Diamondbacks. Mainville spent 13 years in the Minor Leagues with the Baltimore Orioles and Arizona Diamondbacks organizations. He served as the Minor League Medical & Rehabilitation Coordinator from 2007 to 2010 for the Diamondbacks. Prior to the 2007 season while serving in the Baltimore Orioles minor league system, he was the Head Athletic Trainer for the AAA Ottawa Lynx (2004-2006), AA Bowie Baysox (2001-2003), High-A Frederick Keys (2000), Low-A Delmarva Shorebirds (1999), and Rookie Bluefield Orioles (1998). He began his interest in professional baseball as an undergraduate intern with the Baltimore Orioles in 1996 and 1997 while attending East Carolina University. A certified member of the NATA, Mainville later earned his Masters of Science degree in Performance Enhancement from California University of Pennsylvania in 2005. A native of Warrenton, VA, Mainville now resides in Chicago, IL with his wife, Michele, and children Kylie, Caden, and Carter.

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Asst. Athletic Trainer

Nick Frangella

Nick begins his first season as assistant athletic trainer for the Chicago Cubs. He joins the major league staff after serving as an athletic trainer in the Cubs’ minor league system for 13 years. Most recently, Nick served as head minor league athletic training and performance coordinator (2013-2017). Prior to this, he was head athletic trainer for the Iowa Cubs (2012-2013), Tennessee Smokies (2008-2011), Peoria Chiefs (2006-2007), and Boise Hawks (2005). Frangella was an Athletic Trainer for the Mesa Solar Sox of the Arizona Fall League (2011) and has also earned Southern League Athletic Trainer of the Year honors in 2009 while with the Tennessee Smokies. Nick served as PBATs Athletic Training intern for the Chicago Cubs during the 2004 season at the major league level. He earned a Bachelor of Science degree from Illinois State University in 2004 and a Masters Degree from California University of Pennsylvania in 2007. Nick was raised in Oak Forest, IL and resides in Normal, IL with his wife Becky.

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Asst. Athletic Trainer

Matt Johnson

Matt is in his seventh season as assistant athletic trainer for the Chicago Cubs.  Matt joined the Cubs’ major league staff after serving as an athletic trainer in the Cubs’ minor league system for 10 years.  Matt has made stops at Mesa (Rookie), Boise (Short-Season), Peoria (A), West Tenn. (AA), Tennessee (AA), and Iowa (AAA).  Matt was the athletic trainer for the Iowa Cubs from 2008-2011.  In 2008, he also served as the athletic trainer for the Aguilas de Cibaenas in the Dominican Winter League.  Matt graduated from Ohio University with a Bachelor of Science degree in athletic training.  He earned a Master’s degree from Boston University in applied anatomy and physiology.  Matt is a Certified Athletic Trainer (NATA), Certified Strength and Conditioning Specialist (NSCA), a Corrective Exercise Specialist and Performance Enhancement Specialist (NASM), has his CFAS (Gray Institute) and is ASTYM Certified.  Matt was born and raised in La Grange Park, IL.  He and his wife Rachel, reside in Stow, Ohio with their kids Sam, Brian and Maggie.