The Arizona Diamondbacks saw their pitchers experience a sharp bump in effectiveness last season, something Mike Hazen credits to an emphasis on defense-first catchers.

They rotated Jeff Mathis, Chris Iannetta and Chris Herrmann in 2017, but Iannetta signed with the Colorado Rockies in free agency. They also have John Ryan Murphy on the 40-man roster.

"We want the catchers to take care of the pitchers first and foremost and run the game and make sure we're pitching night in and night out," Hazen said. "We feel that's the best path to success. We would be comfortable going into the season with the catching configuration we have. We're not tied to two or three catchers, but I do think the three-catcher system worked out pretty well for us."