Left-hander Robbie Erlin hurled a scoreless first inning with one hit, as he opened his bid for a spot in the back of San Diego's rotation.
"It's pretty cool. Definitely exciting," Erlin said of getting the first start of spring. "It felt good. I was a little up in the zone today. I was probably a little overanxious, but I've just got to get the ball back down, get a feel for it, get up to game speed."
Paxton is in a similar competition for a final rotation spot for Mariners and the 27-year-old gave up just one walk with no hits in a 34-pitch outing with one strikeout and no balls hit out of the infield.
"It felt really good to be back out on the mound facing guys that aren't on our own team," said Paxton, who was limited to 13 starts last year by a torn finger tendon. "For the first time out, I felt like I was pounding the strike zone pretty well. I tried to do too much on a few pitches, but I felt like it was a really good starting point for Spring Training."
PADRES UP NEXT: Philip Humber will get the start Thursday when the Padres face the Mariners for the second time in as many days. First pitch is scheduled for 12:10 p.m. PT. Humber, in camp on a Minor League deal as a non-roster invitee, faces a steep challenge to make the roster. He pitched last season in Korea before being released in July. He does have some history against the Mariners, though. In April 2012, Humber tossed a perfect game against Seattle at Safeco Field.
MARINERS UP NEXT: Nathan Karns makes his Mariners debut in Thursday's rematch with the Padres at Peoria Stadium. The 28-year-old right-hander was 7-5 with a 3.67 ERA in 27 games for the Rays last year. Joe Wieland, another starter acquired from the Dodgers, will follow Karns on the mound. Starting infielders Robinson Cano, Ketel Marte and Kyle Seager will be among the position players used by manager Scott Servais. The game will be broadcast live on 710 ESPN Seattle.
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB, read his Mariners Musings blog, and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.