Jim Hallman, Owner
Mick Delaney, Manager
Mick has been at Grand Slam since 2014. He is in charge of the day to day office operations as well as doing both group and individual lessons. Mick averages over 20 hours of lessons per week doing both hitting and catching lessons, as well as working with High School Softball teams for their offseason hitting programs. Throughout the year Mick has over 70 clients he works with for both Baseball and Softball. He is entering his 12th year as a High School Baseball coach. For 5 years Mick was the Varsity Hitting and Catchers Coach at Urbandale High School helping lead the J-Hawks to back to back State Championships in 2018 and 2019. He is in his third year as the Varsity Hitting and Catchers Coach at Northwest High School in Waukee.
Photo Credit: Alli Stuhr Photography
Photo Credit: Alli Stuhr Photography
Photo Credit: Alli Stuhr Photography
Mike Joseph, Instructor (hitting and catching), Slammers Coach and Staff
Mike is beginning his 6th year instructing with Grand Slam serving as our lead catching instructor. Mike graduated from Dowling Catholic High School and went on to play college baseball at St. Olaf College in Northfield, Minnesota. He has an extensive coaching background at the high school and club levels, having coached at Roosevelt, Dowling Catholic, and currently serving as assistant coach with Jim's 18U Iowa Slammers fastpitch club.
Mike is also the manager of Grand Slam Strength, the Strength and Conditioning program.
Outside of Grand Slam, Mike is married with 4 children and works full time home remodeling and carpentry.
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Austing Errthum, Mental Performance Coach (CMPC)
Austin Errthum has been a Certified Mental Performance Coach (CMPC) since 2022, earning his master's in Sports and Exercise Psychology after previously teaching and coaching in the Des Moines area. Austin specializes in helping athletes perform optimally by creating a mental toolkit that builds confidence and handles pressure effectively. He has worked with athletes ranging in age from 9 to the professional level. Austin played both Division I football and soccer in college before earning a brief stint with the Kansas City Chiefs in 2019. In his free time he loves to travel, watch the Red Sox, and spend time with his family.
Luc Farren, Instructor
Luc joined the Grand Slam staff in August of 2022, serving as a hitting instructor, running many of our youth hitting clinics as well as individual lessons. He also assists in the Grand Slam Baseball Club, running practices for several of our teams. Luc is originally from Illinois, coming to Iowa to play baseball at Central College. At Central, he was a team captain for 3 years, and assisted in leading individual and group hitting and fielding development sessions.
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Trey Widhlam, Instructor
Trey played Shortstop at Pleasant Hill High School in Missouri. He played college ball for three years at Grand View University as an outfielder before retiring due to a shoulder injury. He is currently a student coach for Grand View, and coaches at US National in KC, MO.
Brock Sailer, Instructor
Brock joined the staff last year, instructing many of our Pitching and Fundamentals clinics, as well as offering individual lessons in those areas. He also coaches for the Grand Slam fall league. Brock graduated from Waukee High School. He went on to pitch collegiately at Iowa Central CC and earned his associate degree. Brock then went to Grand View University to continue playing baseball and finish getting his bachelor’s degree in liberal arts. Outside of Grand Slam, Brock enjoys spending time with his girlfriend, friends, and family, taking in what life has to offer.
Jesse Correll, Instructor, Slammers Coach and Staff
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Anthony Moist, Player, Instructor, and Student of the Game
Anthony is a dedicated redshirt freshman at Grand View University, where he continues to pursue his academic and athletic goals. As a passionate baseball enthusiast, Anthony has also established himself as a front desk manager and a baseball and softball instructor at Grand Slam USA, marking his third year as a valued employee.
Under the mentorship of Jim Hallman, Anthony has gained hands-on, professional teaching experience, learning how to effectively communicate and instruct young athletes. His current role as an assistant coach at Grand View further enhances his understanding of coaching techniques, emphasizing the importance of teaching players how to learn and understand the game rather than simply telling them what to do. Anthony believes that guiding players through personalized instruction is crucial to their development and future success on and off the field.
A former three-year varsity starting pitcher in high school, Anthony made a significant impact on his team. During his junior year, he achieved 13 starts with an impressive sub-2 ERA, ranking him among the top 25 pitchers in the state of Iowa. Now pitching at the collegiate level, Anthony is eager to continue developing his skills and compete at a high level.
Beyond his athletic pursuits, Anthony is committed to giving back to the sport that has provided so much for his family. His passion for baseball, combined with his dedication to teaching and mentorship, drives him to help others succeed both on and off the field.
Ryan Hulse, Hitting Instructor
Ryan graduated from Grand View in 2025 and is currently persuing a Masters Degree while playing baseball. He has coached 12U teams for Iowa Sticks the last two summers
Kaleb Krier, Instructor
Kaleb played high school ball at Southeast Polk (all state) and played collegiality at DMACC (All Conference), Valparaiso, and Grand View University (Conference pitcher of the year). He currently coaches at Grand View. Kaleb's is experienced in primarily pitching instruction, along with fielding (infield/outfield) and hitting. His passion for for baseball and youth athletes will help them become the best version of themselves. He is currently a grad assistant at Grand View University where he helps with Pitching.