Wieland was added to the roster for a spot start when Ariel Miranda -- the scheduled starter Friday -- was needed in relief in Seattle's 15-inning victory over the Tigers on Tuesday.
Between the second and fifth innings, Wieland allowed two hits, induced a double play grounder and retired eight consecutive hitters.
"When he's using all his pitches, like he did in the second through fifth [innings], that's what he can do," Mariners manager Scott Servais said. "We feel good about where he is."
Wieland said the biggest difference between pitching effectively in his middle innings was getting ahead of hitters.
"The ball was down and I got ahead, using all my pitches," he said. "Once you get behind you have to throw fastballs. There were some nerves. The first couple of pitches I was trying to get settled in. After that, it was just another start."
Wieland was making his his 12th big-league appearance, and his 10th start. He's now 1-6 in his career.
At Triple-A Tacoma, Wieland was 10-2 since May 4 and won his last five starts before getting the call to start Friday.
"They jumped on him in the first inning but give him credit, he recovered and got on a roll," Servais said. "Bases loaded, a ground ball that gets through the infield. That's going to happen."
The Mariners managed just four hits against A's pitchers. Shawn O'Malley had two of them and Kyle Seager hit a home run.
"We didn't do a whole lot offensively," Seager said. "It was like groundhog day, double play, double play, double play the first three innings."
Seager has hit safely in each of his last six games and is hitting .435 over that span.
Rick Eymer is a contributor for MLB.com based in the Bay Area. This story was not subject to the approval of Major League Baseball or its clubs.