How well Tony Cruz can do playing regularly in place of the injured Yadier Molina is the biggest question facing the Cardinals. (Bill Greenblatt/UPI)

By Rob Rains

As the Cardinals begin the “second half” of the season on Friday night against the Dodgers at Busch Stadium, here are the 10 biggest questions that will need positive answers over their final 66 games if the Cardinals hope to be playing deep into October again this year:

1. What kind of performance can they expect from Tony Cruz?

Any survey of NL GM’s and managers would reveal that the single most irreplaceable player in the league is Yadier Molina. Yet he will not play for a minimum of two months after tearing a ligament in his thumb, with the bulk of his playing time going to Tony Cruz. Cruz is a more than capable backup, but asking him to step into the lineup as a regular in place of Molina for such a long stretch is asking an awful lot from him. The Cardinals were 13-14 in games Cruz started last year, and a .500 record the rest of this season likely won’t be good enough to get the team into the playoffs. What the Cardinals will need is for other players to step up and fill in some of the gaps caused by Molina’s absence, at least offensively, and hope Cruz can hold his own on the defensive side and chip in a hit or two.

2. When will Michael Wacha be back?

This is likely the question John Mozeliak, Mike Matheny and the rest of the Cardinals brass, including the medical staff, wish they could answer because so many of their other decisions as far as trades, minor league promotions, etc., hinge on Wacha’s availability. The Cardinals expect to have another progress report early next week on how rest and rehab has improved the condition of his right shoulder. Even if he gets clearance to begin throwing at that point, however, he is probably at a minimum two or three weeks away from re-joining the rotation. The Cardinals will err on the side of caution as well, not wanting to jeopardize Wacha’s long-term future for a few extra starts this season and they do not want this to be a condition which continues to bother him throughout his career.

3. Will Mozeliak pull off a deal before the July 31 trading deadline?

Part of the answer to this question might depend on what kind of medical report they get regarding Wacha next week. If they think he can be back by mid-August, it does diminish their need for a least a front of the rotation starter. If the report is that he will be out for longer, it would not be a stretch to see Mozeliak see what it would cost to get David Price out of Tampa. The Cardinals have reached a point, no matter what they find out about Wacha, where they would consider packaging some of their higher-end prospects in a deal, but they won’t be able to get both a high-end starter and an impact bat. They also are not willing to give those prospects up for a rental deal, and want to be sure they can keep the player they acquire in St. Louis for several years. If the team does not swing a blockbuster deal, Mozeliak still could try to make a move to strengthen the team’s bench.

4. Can Allen Craig rebound from his poor first half?

This is another question where the answer will have domino effects on other players and other trade discussions. The Cardinals are not likely to give up on Craig because of a few poor months, but the last two months of a season are not the time to simply hope a player can suddenly find his stroke again. With Matt Adams doing well, Craig could find himself on the bench with Oscar Taveras getting the bulk of the playing time in right if he does not show signs of improvement fairly quickly.

5. Will Matt Holliday be able to pick up his offensive performance?

Holliday is one player who can get hot and carry this team on his back for a couple of weeks. What he has working in his favor is that he traditionally plays much better in the second half of the season. He has a career average of .314 in the second half of the year, and last year hit .268 in the first half before posting a .348 average in the second half of the season.

6. Can Trevor Rosenthal hold up from his heavy workload?

Rosenthal’s 28 saves before the All-Star break is the second highest total in franchise history. Most of those saves, especially in June and July, did not come easily as he has allowed either a walk or a hit, or both, in 13 consecutive appearances, although he did earn the save in 10 of those outings, plus one win. He has walked 26 batters in 43 2/3 innings, which is forcing him to throw many extra pitches. With the Cardinals offense struggling, it is likely the team will not be blowing out many of their opponents, which – also because of the back end of the rotation’s inability to pitch deeper in games – likely will create a lot of save situations where Matheny will call on Rosenthal.

7. If Taveras sees significant playing time, how well will he do?

One of the things the Cardinals do not want to do is put too much pressure on Taveras to be the team’s offensive savior. If he is playing, however, they do expect contributions. The party line is that he has done all he can do in the minor leagues, and is ready for the majors – but so far he has a .197 average with the big-league club and has not hit a home run since his second at-bat. He has a .205 average with three RBI in 12 games, nine starts, since he was called back up from the minors for the second time on July 1. How much playing time Taveras gets will depend on whether Craig can start hitting better, and if the team is comfortable enough to start Taveras in center over Jon Jay.

8. Can Wainwright be as good as he was in the first half?

He was the ultimate definition of an ace, posting nine starts in which he allowed no runs in seven or more innings. He was 12-4, and the team was 15-4 in his 19 starts – combined, the team was 37-40 when anybody else started. If the Cardinals can’t get better performances ouf of their other starters they will need Wainwright to be just as good as he was from April that June, if not better, if they are going to stay in the race.

9. Who will step up in the starting rotation?

Despite his critics, Lance Lynn was the team’s second best pitcher in the first half, and the only one (other than Wacha) who the team could realistically count on to get into the seventh inning in most of his starts. Saying that, however, Lynn has pitched better in the first half of the year than he has in the second each of the last two years. He went 11-4 in the first half of the 2012 and 2013 seasons, but was just 4-6 in the second half of last year and 7-3 in the second half of 2012, when his ERA rose by more than a run. Lynn is not the only starter who needs to pitch better. There is definitely room for improvement from Joe Kelly, Shelby Miller and Carlos Martinez, one of whom would come out of the rotation if and when Wacha is ready to pitch – or if they trade for a starter.

10. Can Adams and Kolten Wong continue their recent offensive production?

The two youngsters have been two of the team’s best offensive players the last few weeks with Wong especially providing more power than he had shown previously. A solid performance by Wong could settle the lingering problem of finding a number two hitter in the lineup, and produce more RBI chances for Holliday and Adams behind him. The challenge for all young players, especially for those in the regular starting lineup for the first time, is the length of the season and not wearing down when they start playing deeper into the year than they ever have before. It caught up with Matt Carpenter at the end of last year, and the Cardinals have to hope it doesn’t affect Adams and Wong this season.

Follow Rob Rains on Twitter @RobRains