SEATTLE -- Outfielder George Springer and pitcher Brett Oberholtzer were not even in the Houston Astros' plans when they arrived for a four-game series at Safeco Field on Thursday, but the team was sure glad to have them back Saturday.

Springer returned from a hip injury to hit two home runs and Oberholtzer made the most of his promotion from Triple-A while, picking up his first win in a string of 12 starts in Houston's 9-4 victory over the Seattle Mariners.

"I haven't had fun in awhile pitching," said Oberholtzer, who lost 10 consecutive decisions in 11 starts before getting demoted earlier this month. "Today, I definitely had fun."

Oberholtzer (1-6) won for the first time since Sept. 1, 2013, when he threw a complete-game shutout against the Mariners before suffering losses in each of his four starts to close out the 2013 season.

The 24-year-old southpaw went 0-6 in his first seven starts of 2014 before beating the Mariners again with a six-inning outing. He allowed two earned runs and six hits while striking out a season-high eight in his first game back from a stint in Triple-A.

"Oberholtzer did a great job of attacking the strike zone," said Astros manager Bo Porter, whose team snapped a four-game losing streak behind a season-high nine runs while matching a season-best 11 hits on Saturday. "That's one of the things we talked to him about when we sent him down (to Triple-A)."

Oberholtzer got a lot of help from Springer, whose hot bat picked up right where it left off during his two games of rest. The rookie drilled two-run homers in the first and fifth innings to drive Seattle starter Brandon Maurer (1-3) from the game.

Springer returned from his hip injury and hit the first pitch he saw over the right field fence for a 2-0 Houston lead. He then put the Astros ahead 6-2 with another two-run shot, to left field, in the fifth. Springer finished with five RBIs.

"I don't like not being out there," Springer said of the two-game layoff to rest his hip injury. "I was just happy to help tonight."

Springer's second home run drove Maurer from the game after a 4 1/3-inning, six-run outing. The Astros (18-32) have had plenty of success against Maurer during his two years with the Mariners; Houston's current active roster has now posted a .478 batting average against him.

Maurer now has a 6.99 ERA this season, but Mariners manager Lloyd McClendon was not making any declarations about when he might start again.

"I'm just looking at tomorrow's game right now," he said about 15 minutes after Saturday's loss. "I'm just trying to win tomorrow's game."

Porter was also uncertain about where his rotation stands. Oberholtzer, who did not know he would be pitching Saturday night until he read the news on the team's website that morning, came in to give the other starters an extra day of rest. The status of Brad Peacock (strained forearm) is a factor in how things might shake out.

"We'll figure out where Peacock will slot back (into the rotation) and then make a decision," Porter said. "But Oberholtzer did a good job today."

Second baseman Jose Altuve, first baseman Marc Krauss and shortstop Jonathan Villar each added an RBI for the Astros. Left fielder Alex Presley scored on a Tom Wilhselmsen wild pitch to draw boos from the Safeco Field crowd.

The Mariners (24-24) have now gone 6-9 against the Astros at home since the start of the 2013 season. Seattle had won the first two games of the current series, but things quickly spiraled out of control Saturday night.

"Not much of a game," McClendon said. "We didn't really give ourselves much of an opportunity."

Houston had scored six total runs during the four-game losing streak before breaking out for nine in Saturday's win.

Springer's second home run, a two-run shot to left field, put Houston ahead 6-2 in a fifth that saw the Astros eventually score five runs while sending 10 batters to the plate.

Villar had an RBI and scored from first base on an Altuve single -- thanks to a mental error from Mariners right fielder Michael Saunders, who threw to the wrong cutoff man.

Springer opened the game's scoring with a two-run homer on the first pitch he saw, drilling Maurer's sixth pitch of the game over the right field fence for a 2-0 Astros lead before the Mariners had an out. Springer extended his hitting streak to six games with the homer.

A throwing error on Krauss, who cleanly fielded a Kyle Seager grounder and threw the ball into left field, scored two Seattle runs in the bottom of the first to tie the score 2-2.

NOTES: Houston starter Brett Oberholtzer was making his first start since May 6, having spent 2 1/2 weeks at Triple-A after an 0-6 start with the Astros. ... Mariners SS Brad Miller, who is hitting .156, has been benched for three consecutive games. Willie Bloomquist was at shortstop for the second game in a row on Saturday. ... Astros RF George Springer was 0-for-11 with four strikeouts at Safeco Field this season before hitting the first pitch he saw over the right-field fence for a first-inning home run on Saturday. ... Mariners CF James Jones had a second-inning groundout overturned by instant replay challenge. Replays showed that Jones beat the throw from third base for an infield single, extending his hitting streak to 14 games. ... Saturday's game came on a Turn Back the Clock promotional night, with both teams wearing throwback uniforms from 1979.