Mariners trade top prospect O'Neill - Langley Advance Times
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Revisiting the St. Louis Cardinals trade for Tyler O'Neil
Cardinals acquire Tyler O'Neill from Mariners
Top 10 Prospects The Mariners Traded Away — College Baseball, MLB Draft, Prospects - Baseball America
Mariners Flip Tyler O'Neil for Marco Gonzales: Yawn or Yay?
Mariners send prospect Tyler O'Neill to Cardinals — Canadian Baseball Network
Cardinals To Promote Tyler O'Neill - MLB Trade Rumors
Mariners trade prospect Tyler O'Neill to Cardinals for LHP Marco Gonzales - Seattle Sports
3 players the Mariners wish they still had on their roster