"I guess that remains to be seen," Berkman said after Houston's 4-3 victory over the Texas Rangers on Tuesday gave them three wins in their last 12 games.
Berkman had a two-run homer among his two hits to break out of a three-game hitless streak for Houston, which had to hold on in the ninth.
The Astros led 2-1 before Berkman's homer off Joaquin Benoit that landed in the bullpen in right field and scored Miguel Tejada in the eighth inning. Berkman was 0-for-9 in the weekend series with Tampa Bay, his first series this season without a hit.
Berkman broke his skid with a double in the second inning and tied it at 1 when he scored on a single by Ty Wigginton.
"I felt pretty good in Tampa," he said. "Baseball's a funny sport. I've yet to be able to explain why things like that happen, but I'll take two hits tonight."
Humberto Quintero's first RBI of the season, a double in the second inning that rolled into the left-field corner, scored Wigginton and gave Houston a 2-1 lead.
The Rangers had a chance to take the lead in the eighth inning after a walk by Michael Young and a single by Brandon Boggs. Houston replaced Doug Brocail with Valverde and Young and Boggs had a double steal with Marlon Byrd batting.
But Valverde struck out Byrd to get out of the inning before Berkman stretched the lead with his 21st homer.
David Murphy's double to center field with one out in the seventh inning chased Astros starter Brian Moehler (4-3). He was replaced by Wesley Wright, who walked Jarrod Saltalamacchia. Wright got out of the inning after Vazquez grounded into a forceout and Carlos Lee snagged Milton Bradley's fly to left field.
Moehler allowed five hits and one run with five strikeouts.
"He's been really, really good for us," manager Cecil Cooper said. "He had been real effective. Moehler was just outstanding to hold them to one run."
Hamilton was replaced by Boggs in the bottom of the fifth inning and the team said he had inflammation in his left knee. Hamilton, who leads the majors with 76 RBI, was 0-for-2 on Tuesday and is day-to-day.
Rangers manager Ron Washington said a doctor examined Hamilton's knee and there was no structural damage.
"He just came in after his last at bat and said he felt something back there," Washington said. "We just didn't want to take any chances. He said it felt a little tight."
Hamilton had two operations on that knee in 2006 and said he believes he injured it last week making a diving catch against Atlanta.
"I felt it in Washington, but it just bothered me when I sprinted," he said of the weekend series against the Nationals. "It didn't bother me when I jogged. I didn't feel it again until I stepped on the top step of the dugout to go out for my first at bat."
Moehler allowed two singles before walking Young to load the bases in the sixth inning. He pitched out of trouble when Michael Bourn caught a flyball to center field by Boggs for the third out.
Kinsler doubled and scored on a single by Young in the first inning to give Texas a 1-0 lead.
Byrd made an impressive, run-saving catch in the sixth inning when he sprinted to the right center field wall to grab a fly from Wigginton with runners at first and second.
Rangers starter Eric Hurley (0-1) failed to get his first win in his third major league start. The rookie did get his first hit with a single in the sixth. He allowed six hits and two runs in six innings.
- Murphy, born in Houston, made his Minute Maid Park debut Tuesday.
- 2B David Newhan entered for the Astros in the eighth inning after joining the team from Triple-A Round Rock earlier in the day. His contract was purchased to take the roster spot left open when Kaz Matsui was placed on the disabled list.