O’Brien joined the Mallards in 2016 after spending five seasons in the Houston Astros organization. While new to the Mallards, O’Brien is no stranger to the Quad Cities area: he spent the last two baseball seasons as athletic trainer for the Quad Cities River Bandits, an Astros single A affiliate.
Prior to arriving in the Quad Cities, O’Brien acted as trainer for two other Houston affiliates: the Greenville Astros and Tri-City Valley Cats. He first joined the Astros system after one season as trainer for the Joliet Slammers, an independent baseball team in the Frontier League.
A native of Eagan, Minnesota, O’Brien earned a Bachelor of Science degree in athletic training at the University of Wisconsin-Eau Claire before going on to receive a Master of Science degree in education from Delta State University in Cleveland, Mississippi.