"They're neck and neck," Servais said. "They've both struggled at times, they've both looked okay for an inning or two here or there. It's very close."
Paxton starts Sunday against the Cubs in Mesa, with Karns going Monday against the Royals in Peoria. It might come down to those starts in determining who opens the season with the club, but it's worth remembering that it's a long season and whoever doesn't open the year with the Mariners could be quickly recalled from Triple-A Tacoma if problems arise with any of Seattle's starters.
Backup catcher
Left-handed hitters Steve Clevenger and Rob Brantly are also involved in a close battle behind starter Chris Iannetta.