About | Slammers South

RESULTS DRIVEN

Guided by a staff of MLB alumni and active scouts, our program delivers a professional-grade training experience focused on hitting, pitching, and defensive excellence. We provide 2–3 weekly indoor sessions that prioritize technical precision and skill evolution. Slammers understands and utilizes the latest in baseball tracking technology to assess and teach. To ensure peak performance, we round out our field training with age-specific strength and conditioning, creating a comprehensive development environment that is second to none in Colorado.

Slammers cultivates an elite environment where fundamentals and sportsmanship are paramount. We build player confidence through demanding practice and competition while instilling lifelong values of loyalty, integrity, and hard work. Education is a core tenet: we emphasize academic excellence (GPA/ACT scores) for all high school athletes and educate parents on their role in this holistic development. Every youth player receives the highest level of professional instruction and integrated strength & conditioning, mirroring our most advanced high school levels.

SLAMMERS SOUTH INSTRUCTORS/COACHES INCLUDE:

Former MLB/MiLB Players

Former DI College Athletes

Years Combined Experience

OUR STAFF

Billy Martin

President / Managing Partner of Slammers North

Billy played 4 years at the University of Texas at Arlington and was then drafted in the 34th round by the New York Mets. He was eventually taken in the rule 5 draft by the Arizona Diamondbacks in 1999 and then sold to the Yakult Swallows of the Japanese Central league in 2003. He was later signed by the Washington Nationals for the 2005 season. Billy finished his career as a 3 time minor league all-star with a career .285 batting average and 94 home runs.

He played 8 years professionally at 4 positions (1B, 3B, LF, RF). Billy has been a part-owner and full-time instructor at Slammers since 2005. Billy has a Bachelor’s degree in kinesiology from the University of Texas at Arlington and a MBA from Denver University, as well as being a certified National Strength and Conditioning (NSCA) personal trainer.

Mark Holzemer

President of Slammers Baseball & Softball

Mark, a proud Littleton native and President of Slammers Baseball & Softball, is a former Major League left-handed pitcher with a distinguished 15-year professional career. Drafted in 1987, he pitched for teams including the California Angels, Seattle Mariners, Oakland Athletics, Philadelphia Phillies, as well as Japan. An NJCAA All-American at Seminole Junior College, Mark became co-owner of Slammers upon retiring in 2002. He currently serves as an Associate Scout for the Kansas City Royals, sharing his vast expertise—accrued through over 8,000 private lessons and extensive coaching experience—with players of all ages.

Clint Zavares

Director

Clint Zavaras is a Colorado native who pitched at Mullen High School. His accolades coming out of high school include Dr. Pepper Player of the year and Colorado high school player of the year. He was acquired in the 3rd round by the Seattle Mariners of the 1985 draft. Clint made his major league debut against the Texas Rangers (pitching against Nolan Ryan) in 1989. He signed
with the Colorado Rockies in 1993. Finished his career back with the Mariners in 1995. Clint was honored by being the opening day starting for the Greek National Team in the 2004 Olympics.

Clint has spent the last 15 years giving private instruction to the areas top high school, college, and professional players and has done well over 20,000 private lessons. He’s become a pioneer in the bio-mechanics of pitching; developing one of the nations top Arm Velocity Programs.