Sandlot Coaches 2026-2027
10U Purple
Michael Gautreaux
10U Black
Brian Hampton
11U
Justin Walker
12U
Ryan Stimac
Jon Halland
Owner/Head Coach, 16s/14s
Coach Jon Halland is the Owner of GA Sandlot Baseball. He was drafted by the Seattle Mariners after playing at Arizona State University.
Coach Halland co-founded the Arizona Sandlot Baseball organization in 2004. His goal is to bring his knowledge and experience to Georgia where GA Sandlot will be available at all age levels.
Courtney Smith
Head Coach, 15s/14s
Courtney is a native of the Bahamas where he was the top catching prospect in his class. In 2018 he signed with the Texas Rangers where he played professionally. Courtney has coached an academy in the Bahamas for 2 years where he dedicated himself to player development. He is a certified strength and conditioning trainer and a catcher/fielding coordinator.
Hampton Mamay
Head Coach, 16s/13s
Originally from Georgia, Hampton is dedicated to helping young athletes develop the skills, work ethic, and mindset needed to compete at the next level. His coaching philosophy is centered around a simple belief: "Consistent hard work leads to success." He is passionatete about mentoring players both on and off the field while helping them reach their full potential.
Hampton played four years as a pitcher at Toccoa Falls College, where he earned Scholar Athlete of the Year in 2024 and First Team All-American honors after posting a 3.21 ERA. During his collegiate career, his team made two appearances at the Avista NAIA World Series. He graduated Cum Laude with a degree in Business Administration and a minor in Marketing, and later earned a Master's Degree in Project Management from Louisiana State University.
With over two years of coaching experience, Hampton specializes in pitching development, mechanics, arm care, velocity training, and the mental side of the game. He has developed pitching and strength programs designed to improve performance while promoting long-term arm health and durability. His coaching emphasizes both physical preparation and mental toughness, helping athletes build confidence, stay focused under pressure, and perform at their best.
Hampton's dedication to baseball has driven his success as both a player and a coach. He is committed to developing well-rounded athletes and helping players achieve their goals through hard work, consistency, and a passion for the game.
Michael Gedman
Head Coach, 14s
Michael Gedman is a former two-way Division I and professional baseball player with more than 13 years of coaching and player-developement experience. A UMass standout and Northwoods League All-Star, he went on to play professionally and led the CAN-AM League in complete games.
Gedman's coaching career includes 3.5 years at Division I Bryant University, where he helped guide the program to a 45-win season and an NCAA Regional victory over Arkansas. He later served five season as head coach at Farmingham State, reaching the conference championship game in each of his final two seasons. He has also coached at ABAC and Georgia State and brings 15+ years of private-instruction and travel ball experience.
Baseball is a family legacy for Gedman: his father, Rich, is a two-time MLB All-Star and Boston Red Sox Hall of Famer, and his brother Matt was a Red Sox draft pick and five-year professional player.
Greg Brown
Pitching Coach/Asst. Coach
Greg Brown is a Marietta, GA native and former University of Tennessee right-handed pitcher. He was selected by the Philadelphia Phillies in the 21st round of the 1999 MLB Draft and played four seasons of professional baseball. Coach Brown brings valuable collegiate and professional experience to player development, giving our players the opporunity to learn from someone who competed at both the NCAA Division I and professional levels.
Dan Rumsey
Asst. Coach
From San Diego, CA; High School - Mt Carmel: All American 1985; College - Arizona State University: All American 1988-1989; Drafted 1989 - San Francisco Giants 1989-1992; Traded to California Angels 1992-1995; California Angels Organization Player/Coach
Present: Asst. Baseball & Hitting Coach - Sprayberry High School
After my professional career in baseball, I have assisted in the coaching arena at the college, high school, and youth levels across the country. My education at Arizona State University was a combination of Kinesiology and Chemistry. As well as coaching baseball, I have assisted athletes from the professional level, down to the age of 13 in strength training, which I believe is paramount for an athlete to perform at their highest level with the lowest possibility of injury. I’ve devoted my life to encouraging and enhancing any athlete that wants to pursue their career in their particular sport. Especially baseball which is my passion. I’ve had the privilege of raising 5 grown children and now am blessed to have 3 grandchildren, which I’m certain there will be more to come in the future.
I look forward to working with the Sandlot and being part of their team and success.
Andrew Swanson
Asst. Coach
Andrew is a dedicated and experienced baseball coach with a distinguished background, both as a player and a mentor. His baseball journey began with a standout collegiate career, earning the prestigious title of 2017 TCCAA Conference Player of the Year and an NJCAA Division I and All-American Honorable Mention. Andrew played one year at Georgia College, two years at Dyersburg State, and concluded his playing career at Tennessee Tech, where he graduated Cum Laude with a major in Interdisciplinary Studies and minors in Exercise Science and Communication.
With over five years of coaching experience, Andrew has developed a comprehensive approach to player development, focusing on hitting, fielding, nutrition, strength and conditioning, and teamwork. He has successfully designed and implemented functional nutrition and training programs tailored to enhance athletic performance. Andrew’s commitment to holistic player development includes mentoring athletes on practical tactics and strategies to overcome failure and mental roadblocks.
Andrew’s dedication to the sport and his players has made him a respected figure in the baseball community, known for his ability to inspire and elevate the performance of his teams and individual athletes.
Waylon Christman
Asst. Coach
Waylon Christman is a former highly ranked baseball palyer who was named a Perfect Game Preseason All-American and ranked among the top two-way players in Georgia during his playing career. With four yeras of coaching experience, Waylon is passionate about developing young athletes both on and off the field. He emphasizes strong fundamentals, confidence, and a positive, competitive environment to help players reach their full potential.