Molina could return to the lineup after receiving positive news regarding his injury, and Wainwright will start one day earlier than scheduled as St. Louis hosts the Houston Astros on Tuesday night.The NL's leading vote getter for the All-Star game, Molina has been sidelined for the past two games due to knee soreness. An MRI revealed no structural damage, though, and the catcher didn't rule out Tuesday as a possible return."Everything came back negative and that's a relief," Molina said.Molina, leading the NL with a .346 average, will be joined by Wainwright, Carlos Beltran -- voted a starter -- Matt Carpenter and Allen Craig representing the Cardinals (53-34) on the NL roster."I didn't think in my life I'd have that many votes," Molina said. "That made me feel good."Wainwright (11-5, 2.36 ERA) ranks among the majors' leaders in ERA and near the top of the NL leaderboard in strikeouts. The right-hander will throw in this contest rather than Wednesday's two-game series finale in order to get two more starts before the exhibition. He'll also start Sunday against the Chicago Cubs.He last pitched Thursday and did not get a decision as he allowed four runs in eight-plus innings of a 6-5 loss to the Los Angeles Angels."I think what's more important is what's going on inside this clubhouse, and can I help the team in that capacity," Wainwright told the team's official website. "I think I can and I think our staff has trust in me to do that as well. Two more starts before the break gives us a good chance to win those games."Wainwright's history versus Houston suggests St. Louis should have a solid chance to win at least that first outing. He's beaten the Astros more than any other team, going 12-1 with a 1.44 ERA in 14 career starts, and has won six straight against them while allowing four runs in 45 2/3 innings.Bud Norris has faced St. Louis more than any other club, and he'll take the mound Tuesday looking to improve on his 2.74 ERA in 15 career starts against the Cardinals.Norris (6-7, 3.22) has been one bright spot in an otherwise disappointing season for the Astros (32-57), who have the most losses in baseball. He's 2/3 with 2.29 ERA over his last nine starts, tossing at least six innings in each after giving up one run in seven frames Wednesday as he defeated Tampa Bay in a 4-1 win."Bud has been absolutely outstanding for us," manager Bo Porter said. "I think he's throwing probably the best he has all season. He's our No. 1 guy and has pitched like an ace."The right-hander will face a St. Louis team that had lost eight of 11 -- all against the AL -- before a three-game sweep of Miami over the weekend. Beltran had two hits and Matt Holliday homered in Sunday's 3-2 victory.Part of the Cardinals' previous slump was a 4-3 loss to Houston on June 26 as the teams split a two-game set.The Astros have dropped eight of 10 since that contest and fell 5-4 to Texas on Sunday. Catcher Jason Castro, the team's lone All-Star, didn't start but popped out to end the game pinch-hitting.The Cardinals have won 11 of the last 13 matchups, including six straight in St. Louis.