ST. LOUIS -- Though the Cardinals enter October with no defined role for Edward Mujica the organization has decided to make the veteran right-hander a part of its playoff roster. Certainly the Cards will have to be selective on when they employ Mujica, but it will be the youngsters who have the biggest impact on St. Louis' relief results.

NLDS

The Cardinals are carrying six rookie pitchers on their postseason roster, and all six will be available out of the bullpen in Game 1 of the National League Division Series against the Pirates on Thursday (4 p.m. CT on TBS). That includes Michael Wacha and Shelby Miller, one of whom likely won't pitch out of the 'pen, but instead step in to start Game 4, if necessary.

 "I need them to truly believe that what they've done so far this year is exactly what they need to continue to do," manager Mike Matheny said. "Regardless of how many questions they get, regardless how many people try to tell them it's different, it's not. It's the same game. It's still 60 feet, 6 inches and 90 feet to each base. They need to believe that and understand that the expectation is no different from me or anyone on the coaching staff. It shouldn't be any different for them on themselves."

At age 23, Trevor Rosenthal, whether he has the title or not, is poised to serve as the team's closer. Kevin Siegrist and Carlos Martinez will both be in the mix for setup roles. Seth Maness has handled the seventh for much of the season but has also become the go-to guy when the team needs a ground ball. This group of young pitchers thrived during the regular season, but the postseason stage does come with added pressures and new distractions. Still, the Cards remain unhesitant to thrust several inexperienced relievers into key late-inning roles.

Wacha and/or Miller won't be limited to pitching only in long relief.

The advice that they have all received from the veterans in the clubhouse is to approach what comes in October no differently than they would an outing in June. Minimizing the moment helps protect against trying to do too much.

"It's going to be noisy, it's going to be crazy, it's going to be fun, but you just have to remember to breathe, take that deep breath and throw that pitch the way you would during the regular season," said John Axford, who pitched in the postseason with Milwaukee in 2011. "Don't try and do too much, don't try and do things that you didn't do during the season. Every one of these guys had success during the year, and great success. They got that for a reason, they did that for a reason, and it's how they approach the game, how they approach hitters. That's what they need to keep doing."

The Cardinals have had success leaning on young arms in past postseason runs. Back in 2006, it was rookie Adam Wainwright who took over as the team's closer when Jason Isringhausen went down with a late-season injury. In 2011, Jason Motte grabbed ninth-inning duties just a month before the playoffs opened. Rookies Lance Lynn and Fernando Salas were also key parts of that postseason 'pen.

Both of those seasons culminated with a World Series championship.

"Well, [in] '06, I think one thing that really helped me was that [then-manager] Tony La Russa and [then-pitching coach] Dave Duncan just brought me along at the perfect pace," Wainwright said. "They didn't throw me in the fire too early. They started me as the long man, and I pitched the seventh inning, then I pitched the eighth inning, and when I was thrown into the ninth-inning role at the end of the season, I was ready for it because I had faced all the big league moments. There was nothing to be scared of at that point.

"That's kind of where our guys are now. If you look at where Carlos Martinez is pitching in the game, he started out as a starter in the Minor Leagues, came in, pitched in some long-inning relief places for us, and now he's throwing a hundred miles an hour out of the back end of the bullpen. So is Trevor Rosenthal. I think our manager and pitching coach, just like Tony and Dave did, have brought those guys along at the great pace that they have."

Rosenthal introduced himself to the baseball world last October, when he shined in seven relief appearances. Used mostly in the middle innings, Rosenthal allowed just two hits and struck out 15 in 8 2/3 innings. That positioned him to open this season as the team's eighth-inning setup man; he was then the natural fit to slide into the closer's spot last week.

In three September save opportunities, Rosenthal did not allow a hit.

Siegrist enters October on a run of 28 scoreless innings. Martinez, who was pushed into higher-leverage roles as September progressed, was scored upon just once in his nine outings last month. Maness induced an NL reliever-high 16 double plays in 66 outings.

"I think if you approach it the right way, one pitch at a time, it takes care of itself," Rosenthal said of the added October pressure. "Obviously the crowds are going to be a little bit louder, and there are even more eyes on you. But it's still the same game, and I'm going to try to approach it that way."