St. Louis Cardinals slugging outfielder Matt Holliday missed Game 6 of the National League Championship Series on Sunday with back spasms. He returned for Monday’s Game 7. (Ben Margot/Associated Press)

St. Louis Cardinals’ slugger Matt Holliday, who was a late scratch from Game 6 of the National League Championship Series with back spasms, returned to the starting lineup for Monday night’s Game 7 after a day of treatment satisfied team officials that he was ready to play.

“I don’t think we’d stick him out there if we didn’t think he was capable of delivering,” Cardinals General Manager John Mozeliak said prior to Game 7.

Holliday’s availability, though, brought up an interesting debate for St. Louis fans. Holliday, the Cardinals’ third-place hitter all season, entered the decisive game against the San Francisco Giants 4 for 21 (.190) in the series, with no extra-base hits. Indeed, in 11 postseason games this year, he is hitting just .222 and slugging .311 — and the back issues have been there all along.

“I think it’s been bothering him for some time,” Mozeliak said. Cardinals officials first noticed the impact on Holliday in his first at-bat in Game 5, Mozeliak said.

The other intriguing element: Matt Carpenter, the role player who would have been inserted into the lineup in Holliday’s stead, was 5 for 6 in his career off San Francisco right-hander Matt Cain, the Game 7 starter. When St. Louis right fielder Carlos Beltran went down with a balky knee in the first inning of Game 3, Carpenter replaced him and hit a two-run homer that delivered the Cardinals’ 3-1 victory.

“He’s been a great fill for whatever we need,” Cardinals Manager Mike Matheny said. “But you start looking at him playing in the outfield in the corners, and you’ve got Matt Holliday and Carlos Beltran, and Allen Craig and David Freese on the corners in the infield. Those are guys that have all been valuable parts of our lineup.”

Backs against the wall

When the Giants made their unlikely run to the 2010 World Series championship, they never faced a decisive game in the postseason. They beat the Atlanta Braves in four games in the division series, the Philadelphia Phillies in six games in the NLCS and the Texas Rangers in five games in the World Series.

This season, they played — and won — a decisive fifth game in the division series against Cincinnati, and then faced the Cardinals on Monday night.

“It’s a big game, but you have to remember how hard that you did have to work to get here,” Giants Manager Bruce Bochy said. “And particularly this club, with what we have been facing here in the postseason. So we could really consider ourselves fortunate to bring it to this point.”

The Cardinals, meantime, have played just one short of the maximum playoff games over the past two seasons. On the road to the 2011 World Series title, they needed five games to beat Philadelphia in the division series, six games to beat Milwaukee in the NLCS and seven games to take the World Series from Texas. They followed that with a five-game series against Washington this year, leading to the NLCS against the Giants.