HOUSTON (AP) -- Astros manager Bo Porter has no plans to shake up his starting rotation despite its recent struggles. Not yet, anyway.
"It's going to have to be a few more starts for me to start thinking about making changes," Porter said after a 7-1 loss to the Seattle Mariners on Monday night. "Those guys earned the right to start."
Still, he needs the group to turn things around soon.
Right-hander Brad Peacock was rocked for three home runs, continuing a troubling trend for the starters, and the Astros lost for the eighth time in nine games.
It was Houston's third straight defeat at home. At 5-14, the Astros are off to the second-worst start in franchise history. They opened 4-20 in 1969, according to STATS.
Felix Hernandez pitched six scoreless innings for his 100th career win, helping Seattle snap a three-game skid. Kyle Seager, Jesus Montero and Kendrys Morales homered for the Mariners.
"Felix was good as usual. He's one of the better pitchers in our league," Porter said. "But we didn't pitch well. When you don't pitch well you put yourself in a hole against a guy of his caliber, fighting an uphill battle."
Astros pitchers allowed three or more home runs for the third consecutive night. Houston has been outhomered 10-4 over the past three games.
Starting pitching was the Astros' strong point to start the season, but the group appears to have hit a "bump in the road," as Porter has called it.
Over the past seven games, only Bud Norris and Lucas Harrell have made it past the fourth inning. Of the starters who didn't, three -- Norris, Erik Bedard and more recently Philip Humber -- failed to make it out of the first.
Their combined ERA during that span? A bloated 15.56.
Peacock (1-2) gave up seven runs on nine hits -- both season highs -- over 4 1-3 innings. Five of the seven runs came on homers in the third, fourth and fifth.
"I didn't have it tonight," Peacock said. "I was getting behind in the count. I've got no excuses. I just have to keep working. I need to get ahead. I fell behind on almost everybody tonight."
Not that the offense has held up its end of the bargain. Despite hitting 21 home runs through 19 games after hitting only 14 through 22 games in April last season, the Astros have been outscored 64-29 in the last nine games.
"It's tough," first baseman Carlos Pena said. "We take pride in what we do, and every time we lose it eats away a little piece of us, there's no doubt about that."
Houston reliever Jose Cisnero made his major league debut when he replaced Peacock in the fifth inning. Cisnero was a bright spot for the Astros, allowing two hits in 3 2-3 scoreless innings.
"I think the fact that we made it through tonight's game with one starter, one long guy and one bullpen guy . I think moving forward we should be in good shape," Porter said.
Hernandez (2-2) allowed five hits and struck out nine to lower his ERA to 2.08. He came in with the second-lowest run support in the AL at 1.88, and didn't factor into the decision in his last start despite striking out 12 and allowing no earned runs in eight innings.
Rick Ankiel hit a solo homer in the seventh and Jason Castro went 2 for 3 with a pair of doubles for the Astros.
Seattle got things going early in this one when Seager extended his hitting streak to a career-best 11 games with a one-out single in the first. Morales walked before Seager advanced to third on a passed ball by Castro with two outs.
Justin Smoak sent Seager home with a single that glanced off Pena's glove and into the outfield to make it 1-0.
Seager put the Mariners up 3-0 in the third when he launched a two-run homer to the second deck in right field. He has scored six runs and driven in eight during his hitting streak.
Montero added a two-run shot to center field in the fourth to push the lead to 5-0.
Morales led off the fifth inning with a home run to right field to make it 6-0. Smoak doubled and scored on a sacrifice fly by Montero later in the inning.
The Astros couldn't string any hits together against Hernandez. The only time they had more than one runner against him was in the fourth, but thanks to a baserunning gaffe that didn't last for long.