JUPITER, Fla. -- Cue the countdown. Thursday marked the start of a final month-long sprint for the Cardinals ahead of their season opener at Miller Park against the defending division champs on March 28.

“I love where we’re at with a month to go,” manager Mike Shildt said after the club’s 3-2 loss to the Mets. “I’m very excited about where we are and we’re ahead of where I’d even like to be at this point in camp.”

But that doesn’t meet their work is done. Over the next four weeks, the Cardinals will be charged with whittling a 65-man camp down into a 25-man roster. Competitions must be settled. Roles will need to be defined. Injuries risk complicating it all.

So with the clock ticking, here’s a look at seven pressing questions -- along with MLB.com’s prediction as to how each will be answered -- still facing the Cardinals as the calendar flips to March.

Who becomes the fifth starter?

This is suddenly (and unexpectedly) the most intriguing battle in camp. Carlos Martinez’s injury created a wide-open competition for the team’s final rotation spot, and there are five pitchers currently in the mix -- John Gant, Austin Gomber, Dakota Hudson, Daniel Ponce de Leon and Alex Reyes. The Cardinals won’t be able to stretch all five out in Grapefruit League games for much longer, so look for the group of competitors to be narrowed to two or three by mid-March.

Prediction: The job he did as a starter last season, coupled with his status as an out-of-options player, makes for easy justification to give Gant the first crack.

What will become of Martinez?

Martinez will remain on a no-throw program until around March 12, at which time he’ll have his right shoulder re-evaluated. Those tests will determine whether Martinez can resume throwing, or if he’ll have to spend additional time strengthening the muscles around his shoulder. All this will also factor into a decision about Martinez’s fit. The Cardinals are open to considering Martinez for a relief role if there are concerns about durability.

Prediction: Martinez will open the season on the injured list while giving it one more try to build up as a starter. Relieving will remain his fallback option.

How will Reyes start the season?

As long as his session of live batting practice goes well on Friday, Reyes will make his Grapefruit League debut next week. That’s sooner than expected, which is an affirmation of how smoothly Reyes has rebounded from a second arm surgery in two years. The Cardinals haven’t counted him out of the competition for an Opening Day roster spot -- as either a starter or reliever.

Prediction: The team will buy extra time by keeping Reyes back in extended spring training before having to decide how to balance potential impact, workload limitations and future health for its top prospect.

Will Marcell Ozuna’s shoulder be ready?

Both the Cardinals and Ozuna insist there’s nothing to worry about, but there has also been no firm timeline as to when he’ll be ready to play the field this spring. That’s reason for at least a hint of concern, as he’s now four months removed from shoulder surgery. While Ozuna continues to build up arm strength in a throwing program, he’ll be used solely as a designated hitter until further notice.

Prediction: Ozuna will be in left field for the Cardinals on Opening Day, but with a shoulder that is still not 100 percent.

Who will back up Yadier Molina?

This became a question with the team’s decision to ink Matt Wieters to a Minor League deal this week. That puts Wieters in competition with Francisco Pena and Joe Hudson for the job of backing up a nine-time Gold Glove Award winner who, barring injury, could again start 130 games behind the plate.

• Wieters relishing new role with Cards

Prediction: The experience and switch-hitting ability of Wieters becomes too enticing for the Cards to pass up. He wins the job over Pena.

Will Dexter Fowler open the season batting second?

Though he’s not yet committed to it, Shildt has already used Matt Carpenter, Fowler and Paul Goldschmidt (in that order) atop his lineup three times this week. It’s a lineup possibility Shildt is considering, but Fowler’s spring showing will play some role in whether it sticks. So far Fowler is hitless in seven spring at-bats.

Prediction: Shildt will drop Fowler to sixth in the batting order for the start of the season, elevating Goldschmidt to the second spot and Paul DeJong to third.

Will the Cards start with a 12- or 13-man pitching staff?

The Cards haven’t yet shown their hand on their preference, perhaps knowing it will create a cascade effect. If the Cardinals carry seven relievers, that’ll be an extra bench spot available for someone like Tyler O’Neill, Drew Robinson or Yairo Munoz. Taking an extra pitcher could make it easier for the Cards to find room for Reyes or Martinez or one of the young starters squeezed from a rotation spot. It could also justify carrying as many as four lefty relievers.

Prediction: With only two off-days scheduled over the first 15-days of the season, the Cardinals will choose the extra pitcher.