Lewis gave up five hits, struck out three and walked one.
Lewis, the 2012 Rangers' opening-day starter, is coming back from hip and elbow surgery. He has not pitched in the majors since July 27, 2012, and Texas plans to start him in the minors as he builds up strength.
"I'm healthy," Lewis said. "Write what you want to write. I'm really not in a mood to be talking. That's all I've got."
Lewis was not happy he was left out of the Rangers' starting rotation, which includes Tanner Scheppers and Robbie Ross -- who have been used strictly in relief in the majors -- and minor leaguer Nick Martinez, who was not in the big league camp.
Lewis is scheduled to start a minor league exhibition game Tuesday at Round Rock against Fresno, the Rangers' Triple-A and Double-A affiliates.
"I guess," Lewis said. "I go as directed, right now."
Lewis lowered his ERA from 18 to 8. In his previous start against major league competition, he yielded five runs on five hits, including two home runs, and three walks in 1 1/3 innings against Oakland.
"He threw the ball well today, 72 pitches, five innings, moved the ball around," Rangers manager Ron Washington said. "He kept his fastball out of the middle of the plate and was able to spot it like he wanted to."
Mariners right-hander Erasmo Ramirez held Texas to one run and three hits, walking none and striking out six in five-plus innings.
Justin Smoak hit a two-run homer for the Mariners.
Mariners: Ramirez has a 1.14 ERA in six outings, allowing just one run and seven hits, while striking out 10 and walking none in 11 innings in his final two starts.
"Today every single thing was working," Ramirez said. "I just have to continue to do what I've been doing on what's going on in this spring training. I'm happy with what happened today and the last games."
Rangers: Lewis gave up a double and three singles in his longest spring outing.
Martinez thought he would open the season with Double-A Frisco, where he finished last season. Instead, he was told Wednesday he would be the No. 5 Rangers starter.
"Surreal, I can't believe it's happening," Martinez said. "I was a little shocked at first. It still really hasn't set in. It's been pretty crazy so far. I think my dad might still be crying."
Dustin Ackley singled in the sixth and has hit safely in 20 of 22 games, batting .406. Brad Miller went 1 for 2 with a walk and is hitting .439, tops in the Cactus League. Robinson Cano's average dipped to .435 after going hitless in three at-bats with a strikeout.
Among the Rangers' plethora of roster moves, they made two waivers claims: veteran infielder Donnie Murphy from the Chicago Cubs and right-handed pitcher Seth Rosin from the Los Angeles Dodgers. Rosin, a Rule 5 draft pick, has never pitched in the majors.
Mariners: Corey Hart (right forearm stiffness) has not played since March 20, but is getting at-bats in minor league games.
Rangers: Yu Darvish got a positive report on his stiff neck after being examined Wednesday by Dr. Keith Meister in Dallas. There is no structural damage and no injection will be needed.
"It's as good as news we could have gotten," Rangers assistant general manager Thad Levine said. Darvish will resume playing catch Saturday, but will start the season on the disabled list to regain stamina and arm strength. He has not pitched since March 16.