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Coaching Staff

Jon Peters
Field Manager

Jon Peters will coach third base and act as an assistant coach with emphasis on infielders and hitting. He spent three years coaching third base, hitters, infielders at Folsom Lake College. Peters grew up in Chino, CA where he was a standout baseball player at Chino High School, earning All-League, All-County, and All-CIF honors. He continued his playing career at Mt. San Antonio Community College for two years and earned a scholarship to NCAA Division II powerhouse Chico State. He helped lead the Wildcats to an appearance in the NCAA DII World Series in 2012. JP has been with the Potters since 2018 and has been Ryan Stevens' right-hand-man since. He currently resides in Rocklin, CA while owning and operating a youth development program called Better Baseball Training as a player developer and coach.

Brock Ragatz
Pitching Coach

He earned his MA in Sports Management from Jessup in 2021 and a BS in Sports Marketing and Administration from Northern State in South Dakota where he played 4 years starting in 2016. Ragatz is a Potters alumni who competed for the 2018 Great West League runner-up team. He followed that by being an intern in the 2019 season. This led him to a Grad-Assistant position and then was promoted to Athletic Coordinator position at William Jessup University, just down the road in Rocklin, CA where he assists in recruiting and game-day operations for their sports teams. He began as the Potters' pitching coach in 2022 following a stint as the Jessup pitching coach in their 2021 and 2022 seasons. He now resides in Lincoln, CA with his pup, Mickey. 

Mike Marjama
Assistant Coach

Mike Marjama brings professional baseball experience to the Potters' coaching staff. A 2007 graduate of Granite Bay High School, Marjama attended Sac City College for two years while competing on the Panther Baseball team. He was named a Northwoods League All-Star in the summer of 2010. He transferred to Long Beach State for one year in 2011 and played for the Orleans Firebirds that summer before being selected in the 23rd round of the 2011 Major League Baseball Draft by the Chicago White Sox. Marjama spent time with the White Sox, Tampa Bay Rays, and Seattle Mariners where he was called up in 2017 and was the Opening Day catcher in 2018. He is now a licensed real estate agent focusing on the Sacramento area and also an advocate for National Eating Disorders Association(NEDA) focusing on men who struggle with eating disorders. He currently resides in Granite Bay, CA. 

Cesar Tamayo
Assistant Coach

Tomayo spent 2 years at Marymount California University as a catcher and infielder. He specializes in catching and hitting for the Potters while spending most of his time in the first base coach's box. Prior to Marymount, he played at Mt. San Jacinto Community College. He has since left the LA metropolitan area and resides in Roseville where he is a coach for Better Baseball Training and an instructor at Designated Hitter. 

Emma Hubbell
Head Athletic Trainer

Emma Hubbell has been with the Potters since 2018. She attended received her A.S. in Athletic Training from Ohlone College in 2016 and her B.S. in Atheltic Training from CSU Sacramento in 2017. She also received her Certification in Massage Therapy in 2019 from the National Holistic Institute. She is a Certified Athletic Trainer as of 2018 with other certifications in: Corrective Exercise, Fitness Nutrition, Performance Enhancement, and Basic Life Support. Hubbell is a member of the California, Far West, and National Athletic Trainer's Associations. She continually comes back each summer to #PotterUp and knows Lincoln is her home for the summer. She currently works at Rhodes College as an Assitant Athletic Trainer. Hubbell currently resides in Memphis, TN with her husband, Tyler and kitty, Nala. 

Ryan Stevens

Ryan Stevens
Director of Recruiting

Email : Ryan Stevens

Ryan has led the Potters to 5 consecutive winning seasons with playoff appearances in 4 of them. He finalized his head coach stint with a 2022 West Coast World Series Championship by defeating the Philippines National Team. The Potters led the league in home runs in 2018 and were runners-up in 2021 and 2022. 

After a successful college playing career, Ryan Stevens went on to coach at Sierra College for six years (2011-2016) serving as the hitting coach in a high-powered offense. The Wolverines reached the postseason in each of his six seasons on staff.

In addition to coaching at Sierra College, Stevens served as the head coach and general manager of the Sacramento Scorch Summer Collegiate Baseball Club from 2011-2015.


In 2016, Stevens accepted a position with Louisville Slugger as their Player Insight Specialist where he brings in players of all ages to a state-of-the-art indoor hitting facility located in Roseville, CA to evaluate bat performance for future Wilson/Louisville Slugger products.


2020 gave Ryan the opportunity as a volunteer hitting coach for the William Jessup University Softball team where he is now named the Associate Heach Coach and helped the Warriors to a GSAC Regular Season and Tournament Championship.


Ryan currently resides in Rocklin, CA with his wife, Brittany, and three children, Hudson, Lainey, and Sienna.



Kody Keroher
Director of Player Development

Keroher was the Potters' Pitching Coach from 2018 to 2019 and helped the staff dominate on the mound. He played at and graduated from the University of Nevada Reno after a two-year stint at Solano Community College. In 2004, he was drafted by the Colorado Rockies in the 46th Round of the Major League Baseball Draft. After his playing career, Keroher worked as the Pitching Coach for Solano from 2008 to 2012 where he led the Falcons to five league championships and two Super Regional appearances. He is formerly the Director of Operations and Facilities at Sacramento State University and he and his famIly reside in Rocklin, CA.