KANSAS CITY -- Astros reliever Matt Lindstrom was questionable for Tuesday night's game against the Royals and is still day-to-day with back spasms.

Manager Brad Mills said Lindstrom will be a game-time decision.

"With Lindstrom, we're going to wait and see how he throws today before we make a decision if he's going to be available for [Tuesday night's] game," he said. "After stretching, we'll see how he feels."

Lindstrom hasn't pitched since June 8. On the season, he is 2-1 with a 3.08 ERA and 14 saves.

Reliever Chris Sampson, who is on the 15-day disabled list with biceps tendinitis, will pitch one inning for the Double-A Corpus Christi Hooks on Tuesday night as a part of his rehabilitation stint.

Sampson's last appearance was on May 31 against the Nationals. In 20 innings for the Astros, he allowed 14 earned runs, seven walks and 10 strikeouts.

Berkman rested, ready for Royals series

KANSAS CITY -- After resting during the finale against the Yankees on Sunday, Astros first baseman Lance Berkman was back in the starting lineup for Tuesday's opener against the Royals.

Berkman grounded out to the pitcher in his first at-bat against the Royals, extending his slump to 0-for-15; he went 0-for-4 on Saturday against the Yankees. Berkman is only 1-for-24 in his past seven games after going 12-for-30 in his previous seven.

On the season, the switch-hitter is batting .237 with six homers and 28 RBIs.

Manager Brad Mills said that with Monday being a scheduled off-day, he just wanted to give Berkman some extra rest to rejuvenate him.

"It was nice to have an off-day to be able to charge the batteries and be ready to play," Mills said.

DH provides special challenge for Astros

KANSAS CITY -- With Interleague Play in full swing, Astros manager Brad Mills reflected on the challenges of facing the American League.

Most notable, for Mills, was the role of the designated hitter. The Astros' pitchers will stay put when their team bats, forcing Mills to juggle his lineup.

"The DH is the biggest thing," Mills said. "When we build a team, we really build it without the DH, but these teams in the American League build their team with the DH. So that's the biggest thing that we need to focus on going in."

Jason Michaels got the start at designated hitter for the Astros on Tuesday.

In three Interleague games in American League ballparks this season, Astros designated hitters are 3-for-11 with two RBIs. Through six Interleague games this season, the Astros have a 1-5 record.

Norris' rehab start goes well

KANSAS CITY -- Astros starter Bud Norris is well on his way to returning to the starting rotation.

Norris is on the 15-day disabled list with bursitis and elbow tendinitis, and in his first rehab appearance for Triple-A Round Rock on Saturday, Norris threw four scoreless innings, giving up only two hits and two walks with five strikeouts.

Norris threw 66 pitches, 45 for strikes.

"It was a very good outing," Astros manager Brad Mills said. "He pitched well and threw a lot of strikes. He's doing well."

Norris felt no pain during the start and will make his second rehab start on Thursday.

"He's fine," Mills said. "I think he's going to throw a side session on [Tuesday], and he'll start on Thursday."

In nine starts this season for the Astros, Norris is 2-5 with a 6.80 ERA.