Coaches and Staff

Comer returns to Double-A Frisco in 2026 after managing at the High-A level over the last three seasons. A native of Mansfield, Texas, will enter his 10th season with the Rangers and his second in Frisco.

In 2022, Comer helped pilot the Riders to their second Texas League Championship in franchise history, serving as a development coach. Over the last three seasons, Comer managed High-A Hickory (2023-2024) and High-A Hub City (2025), going 197-191 (.508).

Prior to Frisco, Comer was the hitting coach for the High-A Hickory Crawdads in 2021, after serving as a coach at various levels of the Rangers system from 2016-2019.

The former University of Texas at Arlington catcher played two seasons in the Atlanta Braves organization, reaching High-A Lynchburg in 2012. He was drafted by Atlanta in the 29th round of the 2011 draft after four seasons at UTA.

St. Clair joins the Riders as the pitching coach after leading a Hub City staff that finished third in the SAL with a 3.50 ERA in 2025.

St. Clair enters his fifth season as a Rangers minor league pitching coach and first at the Double-A level, while also serving as the assistant pitching coordinator in the Rangers farm system in 2026.

Initially, St. Clair came to the Rangers as a coach in the Dominican Summer League in 2022 before serving as a pitching coach for the ACL Rangers from 2022-23. Before professional baseball, he spent two and a half years as pitching coach and recruiting coordinator at North Carolina Wesleyan College.

The right-hander pitched three professional seasons in the St. Louis Cardinals system from 2017-19 after he was picked in the 24th round of the 2017 June draft, making 88 outings for the organization’s Rookie and Single-A affiliates.

The Winston-Salem, North Carolina native played four years (2014-17) at Division II Lenior-Rhyne University in Hickory, N.C.

Hart begins his 13th full season with the Texas organization and his ninth as the Frisco hitting coach.

He served as the RoughRiders hitting coach from 2012-2019 before, most recently, serving as the Major League hitting assistant for the Miami Marlins under current Rangers manager Skip Schumaker.

In 2015, Hart was named the Mike Coolbaugh Texas League Coach of the Year for his work with the Riders hitters. Prior to joining Frisco, Hart spent two seasons as the hitting coach with Low-A Hickory. His tenure with the Rangers began after he assisted the Single-A Clinton staff with coaching responsibilities for a portion of the 2008 season and continued when he accepted the role of hitting coach for the Arizona Rangers before the 2009 campaign.

Hart played professionally for parts of eight seasons from 1998-2006, with stints in the Oakland, Texas and Minnesota organizations. He made his Major League debut with the Rangers in 2002, when he batted .267 (4-for-15) with three doubles over a span of 10 games. He missed the 2004 campaign following the removal of a benign brain tumor, but returned to the field in 2005 and hit 21 home runs in 128 games with Frisco.

Originally drafted by Oakland in the fifth round of the 1998 draft, Hart was acquired by Texas in a January 2002 trade with the Athletics. He attended Southwest Missouri State University, where he paced the conference in homers in 1997 and was named a Missouri Valley Conference All-Star in 1998.

Sullenger serves his seventh year in the Texas organization as one of two development coaches on the Frisco staff. He made his professional managerial debut in 2021, leading the ACL Rangers to a 31-28 (.525) record.

Sullenger joined the Texas organization prior to the 2020 season and was slated to coach for Hickory prior to the cancellation of the campaign. Before joining the professional ranks, Sullenger led the baseball program as head coach at Biola University in La Mirada, California, from 2013-2018.

In addition to his work at Biola, Sullenger invested in the local community through baseball camps and working with the Fellowship of Christian Athletes summer baseball team. He began his coaching career in 2000 as a volunteer assistant for the baseball program at James Madison (Va.) University and finished his tenure in 2011 as associate head coach.

Additionally, he worked one season in stadium operations for the Tampa Bay Rays. Sullenger attended Spotswood (Va.) High School and went on to play baseball at Florida Southern College (one season) and Liberty University (three seasons).

He holds a bachelor’s degree from Liberty and earned a master’s degree in Kinesiology with a focus in Athletic Administration/Coaching from James Madison in 2003.

Brown makes his Double-A debut, serving in his third season in the Rangers system.

Before being the athletic trainer for High-A Hub City in 2025, Brown was the ACL Rangers athletic trainer in 2024. He joined the Texas organization in the 2023-24 offseason after completing a student athletic trainer internship with the University of Texas baseball program in 2023.

Brown was also a student athletic trainer at Slinger (Wisc.) High School (2022) and Carroll University in Waukesha, Wisc. (2021). The Louisville, Ky. native holds an associate’s degree in Biology (McHenry County College), a bachelor’s degree in Exercise Science (Upper Iowa University), and a Master’s in Athletic Training (Carroll University).

Additionally, he played four years of college baseball as an infielder and pitcher for McHenry County and Upper Iowa.

Platts joins the RoughRiders for his third season and his fourth in the Rangers organization in 2026.

In his first year, he was the strength and conditioning coach for the Low-A Down East Wood Ducks before spending a season with the Cubs, working in the Dominican Summer League. The Canadian completed his strength and conditioning internship with the University of Iowa athletic department in 2022 and spent four years with the Okotoks Dawgs Baseball Academy from 2019 through 2022.

Platts played two seasons of baseball at Southeastern Community College in Iowa.