ALTON — Marquette Catholic High School has named John Siener as its new head baseball coach, the school announced Thursday, June 12, 2025. Siener succeeds Tim Fahnestock, who retired earlier this month after leading the Explorers for 11 seasons.
Siener comes to Marquette after 14 years as an assistant baseball coach at Fontbonne University, an NCAA Division III institution in St. Louis, Missouri. He brings extensive coaching experience to the role, according to Marquette Director of Athletics Brian Hoener.
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“We are excited to have Coach Siener to lead the Marquette baseball program,” Hoener said. “He brings a wealth of coaching experience to the position, and we believe he will do great things with our student-athletes.”
Siener expressed enthusiasm about his new position and acknowledged the legacy left by his predecessor. “I am honored, humbled and excited to have this opportunity,” he said. “These are huge shoes to fill, but I’m excited to get to work, and I believe my experience makes me a great fit for Marquette.”
Hoener and Siener have a shared history, having worked together at Fontbonne University, where Hoener served as assistant athletic director before assuming his current role at Marquette.
Siener also has strong ties to the Marquette community. All three of his sons graduated from Marquette Catholic High School and played baseball under previous coaches Joe Silkwood and Tim Fahnestock.
“Having watched my three boys thrive at Marquette, I’m very familiar with the school and honored to serve the Marquette Catholic family in this role,” Siener said.
