"I'm content, happy," said Hernandez, whose only complaint was a poor changeup.
Hernandez said he spent his offseason lifting weights in Venezuela with the hope of adding power and improving endurance.
"I look pretty good," said Hernandez, who said his legs feel stronger now than they did a year ago. "I'm trying to look good, you know?"
The 2010 AL Cy Young Award winner allowed a double off the left-center field wall by Yasiel Puig on his first pitch of the game and walked Carl Crawford. Hernandez then induced a 6-4-3 double play from Hanley Ramirez and struck out Andre Ethier.
Brian Wilson, whose 333 regular-season appearances have all come in relief, got the start because of Zack Greinke's strained right calf. Wilson struck out one in a hitless inning.
Crawford, slowed by tightness in his right thigh, played left field for only the second time this spring training.
J.P. Howell allowed three runs and four hits in the third. Puig had an error in the inning, fielding Kyle Seager's single to right and throwing wide of third as Brad Miller scored.
"I thought it was good today," Dodgers manager Don Mattingly said. "I thought our energy was good.
Mariners: Hernandez, who threw 17 strikes on 29 pitches, made his first spring start later than most pitchers. That's part of his usual spring regimen. He's expected to be Seattle's opening day starter for a seventh time, a franchise record.
Dodgers: Wilson has a new role and new repertoire, including a knuckleball. He threw one Tuesday on his first pitch, a strike, to Seattle shortstop Brad Miller.
"It's been a long road," said Wilson, who wasn't in any camp last spring while undergoing rehab for a second Tommy John surgery.
The Dodgers signed Wilson as a reliever last July and re-signed him on Dec. 5 to a one-year, $10-million deal.
Mariners: Seager was back at third base after jamming a finger Feb. 28 in a slide at first against the Padres.
Dodgers: There still was no word Tuesday on when Greinke will work his first bullpen session since straining his right calf on Feb. 27 while throwing only four pitches in a spring start against Arizona. Greinke continued to wear a sleeve on the calf. He walked around the clubhouse without a limp.
"On Zack throwing a bullpen, the calf will tell us when to do it," Mattingly said.
Pitching prospect Ross Stripling is scheduled Wednesday to undergo Tommy John surgery in Los Angeles. A muscle tear in his right elbow was found this week.
"He was a kid who was on a roll," Mattingly said.
Pitcher Stephen Fife was among 10 players cut by the Dodgers, who have begun to trim the roster for the season-opening series against Arizona on March 22 and 23 in Sydney, Australia. Fife, who has been troubled by shoulder tendinitis, started 15 games for the Dodgers over the last two seasons.