AP Baseball Writer
DETROIT (AP) -- Batting leadoff because of an injury to Austin Jackson, Detroit's Andy Dirks hit a drive to center field for a double in his first at-bat.
Three innings later, the 27-year-old outfielder made an even better impression.
Dirks hit his first career grand slam, part of a six-run fourth for the Tigers in their 7-2 victory over the Houston Astros on Monday night. He was at the top of the lineup because Jackson went on the disabled list earlier in the day with a pulled left hamstring.
"I've hit leadoff in college and I've hit leadoff in the big leagues and in the minor leagues," Dirks said. "It's really nothing different. The way I approach it, I just try to get on base for the big guys."
In the fourth, Dirks came to the plate in a good RBI situation -- bases loaded and one out. He drove an 0-2 pitch to right field for his fourth homer of the year.
Houston starter Bud Norris said it was a hanging slider.
"It was the worst 0-2 pitch of my career," he lamented.
The pitch looked just fine to Dirks.
"I liked it," he said. "It's just one of those things in baseball. He didn't mean to leave a pitch over the plate like that, and I was fortunate enough to be on time with it and hit it."
Victor Martinez also homered for the Tigers, who swept four straight from the Astros in Houston earlier this month and opened this three-game series at Comerica Park with another convincing victory.
Anibal Sanchez (4-3) allowed two runs and six hits in seven innings for Detroit. He struck out eight with one walk.
"I feel good," Sanchez said. "My pitches were working good today. I just had a bad inning. That's part of the game."
Houston scored two runs off Sanchez in the third, shortly after Astros second baseman Jose Altuve left the game with a jaw injury following a collision with right fielder Jimmy Paredes on a popup. Norris (4-4) left with lower back spasms after allowing seven runs and nine hits in five innings.
"Altuve came out for precautionary reasons, and he's already told me that he's playing tomorrow," Houston manager Bo Porter said. "Norris wanted to stay out there, but we'll see how he feels in the next day or two. That's always the question when it comes to back injuries."
Houston has lost five straight and 15 of 18.
Detroit trailed 2-1 when Martinez hit a two-run homer in the fourth to give the Tigers the lead. They weren't done. Jhonny Peralta and Don Kelly both singled with one out, and after a walk to Omar Infante, Dirks hit his home run.
Dirks finished with three hits.
Torii Hunter's double in the first scored Dirks to give the Tigers a 1-0 lead. Altuve left the game after colliding with Paredes, but Houston scored a couple of runs in the third to take the lead. Marwin Gonzalez singled and stole second, then scored on a single by Robbie Grossman.
Ronny Cedeno, who came into the game when Altuve left, added an RBI groundout.
But Norris, who has pitched well so far amid Houston's struggles, couldn't hold onto the lead, and his start was cut short by back problems. He left the game after a conference at the mound at the start of the Detroit sixth.
Martinez's homer was his second of the year after he missed all of 2012 with a knee injury.
The Tigers have outscored Houston 44-10 in five games this year.
NOTES: Detroit slugger Miguel Cabrera had his hitting streak snapped at 11 games. ... Tigers RHP Doug Fister (4-1) takes the mound Tuesday night against Houston RHP Lucas Harrell (3-3).
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