JUPITER, Fla. • The Cardinals posted an “A” lineup Tuesday morning for their game against the Miami Marlins. In fact, it might have been their opening-day eight. It included Jose Martinez at first base, hitting fifth.

Martinez, who just before game time was scratched with a minor left groin spasm, would be among the first to tell you that Matt Carpenter is the Cardinals’ first baseman. “That’s his position,” said Martinez. “Carp’s a good player. He can play whatever position he wants and I know that.”

Except that Carpenter hasn’t been anything but a spectator yet, although he appears to progress daily from the lower back ailment that has plagued him for weeks. In drills Tuesday, Carpenter, brandishing a first baseman’s glove, was stationed behind third base, snatching tricky one-hop throws directed at him from anybody fielding a ground ball nearby behind third.

He is swinging a bat now and by the middle of the month, manager Mike Matheny hopes to have him in games. The advantage is that Carpenter can get tens of at-bats on the back fields during minor league games, but time is becoming a factor.

Matheny, asked if he had concern Carpenter would be ready for the season opener March 29 in New York, at first, answered, “No.” Then, he said, “But ... yeah. It’s still early but we’re getting down there where ... things need to be progressing and they are. There is some urgency. If we didn’t see that progression, then there would be some concern. But we’re probably right at that edge, where, if this doesn’t stay on track, I don’t know if he’s going to be timed up. Physically, I think he’ll be ready.”

But Matheny, asked if he would be satisfied at first base with Martinez, who hit .309 with 14 homers as a rookie, answered, emphatically, “Yes.”

“Whatever decision that he makes, I’m going to be cool with it,” said Martinez, who said he hurt his groin lifting weights Tuesday. “Nothing to worry about,” he said, a sentiment Matheny echoed.

Until Martinez returns, which could be in the next few days, Matheny said Luke Voit and Patrick Wisdom would play first and, the manager added, “You might see some (of catcher Andrew) Knizner over there at some point. He’s got a lot of pop.”

Knizner hit a game-tying homer in the eighth inning of Tuesday’s 4-4 tie with the Marlins and Matheny said, “He’s doing a nice job behind the plate, too. Radically improved over a year’s time.”

Looking at the lineup card before he got hurt, the 29-year-old Martinez said, “I was excited to play today. Dex (Dexter Fowler) during stretch(ing) was saying it was good to see everything packed in the lineup. I was being blessed to be a part of it.”

At first base, Martinez still is a work in progress but Matheny said, “So is Carp (who has played less than a year at first).”

Infield coach Jose Oquendo said Martinez was improving at first “but let’s remember it’s only a few games that I’ve seen, so give him some time. He can improve on how he (receives) the ball. The other day, I thought he could have reacted a little better and been better at anticipating one ball that got by.”

But Martinez anticipated correctly Monday when he dashed home from third on a double steal initiated by Voit. A “trick play,” third-base coach Oquendo called it. The Cardinals also stole home again Tuesday, with Fowler performing the theft after the Marlins had tried to pick Tommy Pham off second. And Kolten Wong, who has five steals, probably was safe but was called out at the plate as he tried to score on the front end of a double steal.

“If we do it here, 100 percent we’re going to be doing it in the regular season, so we’ve got to be ready,” Martinez said.

“We’re just trying to be aggressive until we get more stuff going on on the bases. We can’t just stand there and wait for somebody to hit a double or a home run.”

Matheny said he had conversations Tuesday with such veterans as Fowler, Yadier Molina and Marcell Ozuna, telling them he wanted to get some “familiarity” in the lineup. “Not that anything’s written in stone,” Matheny told them, “but this is a potential of who might be around you.”

Houston ran out nearly its best lineup from the World Series championship team on Sunday, and Matheny said, “All right, let’s show some of these teams what we’ve got here, too, because it’s a potentially dangerous lineup from top to bottom. We’ve still got pieces missing that we need to get right and have them be a part of this, but this is just one of those natural steps forward.

“At first, guys just want to get their foot in the water a little, get a couple of at-bats and get out. Now they’re starting to push a little harder, playing back-to-back ... where you can stack those lineups.”

Before the late change, Tuesday’s lineup would have been Fowler, Pham, Paul DeJong, Ozuna, Martinez, Molina, Jedd Gyorko and Wong.

Jack Flaherty, the starting pitcher for the Cardinals on Tuesday, said the lineup “makes it tough for whoever’s going to step on the mound. It gives you a little bit of confidence that we’re going to score some runs.”

Even if Martinez doesn’t start, he will get plenty of at-bats against lefthanders, against whom he was 24 for 59, and key pinch-hitting opportunities in light of his major-league-leading .462 pinch-hit average last season.

“The chances I’m going to play every day are less,” said Martinez, who might have been selling himself short.

“I’ve got to put it in my mind that whatever chances I get, against a lefty or a submariner, I’m going to try to hit the ball.

“I’m not trying to say I’m going to take somebody’s job.”

But, Matheny, asked if he had eight better players than Martinez, responded, “That’s a great argument.”

Rick Hummel

@cmshhummel on Twitter

rhummel@post-dispatch.com