The Mariners added John Stearns to their coaching staff Monday to serve as a seventh coach and a part-time replacement for Jeff Datz, Seattle's third-base coach who was recently diagnosed with cancer.
Stearns will wear No. 52 and fill in at times as the Mariners' third-base coach. He had been working in the Mariners organization as the catching coordinator. He previously served as a scout and, before that, as a Minor League manager in the Blue Jays, Reds, Mets and Nationals farm systems.
When Datz revealed that he had been diagnosed with cancer, he said it was "very possible" he would miss "some" games, though he was still making decisions regarding his treatment. Datz hasn't disclosed the nature of the cancer and said in a statement he is not yet ready to publicly address the issue.
Datz, 53, informed the Mariners on Saturday. He and manager Eric Wedge held a five-minute, closed-door meeting to tell their players. Datz has served as the Mariners' third-base coach for the past three seasons.
Adam Berry is a reporter for MLB.com. Follow him on Twitter at @adamdberry.