Why did Cubs not want to keep Willson Contreras?

Cubs' Happ hits Cardinals catcher Contreras in head with follow-through, then gets hit by pitch - The San Diego Union-Tribune

If Not Willson Contreras, What Are the Chicago Cubs Planning to Do at Catcher? - Bleacher Nation

Cubs hope Contreras continues to grow

Why did Cubs not want to keep Willson Contreras?

Column: Why didn't Chicago Cubs keep Willson Contreras?

Cardinals battle back to beat Cubs, split London Series behind Willson Contreras' big day

Contreras orchestrates heel turn as Cubs lose to St. Louis

Reflections on the day the Cubs did not trade Willson Contreras and Ian Happ - Bleed Cubbie Blue

Cubs' Willson Contreras: If no extension, free agency would be 'dream come true' - Chicago Sun-Times

Column: Freddie Freeman saga a warning for Willson Contreras

Cubs Trade Rumors: Teams Worry How Willson Contreras Would Mesh with New Pitchers, News, Scores, Highlights, Stats, and Rumors