MILWAUKEE -- One of the main reasons prognosticators expected the St. Louis Cardinals to struggle before the season was a pitching rotation that included a motley crew of journeymen.

By mid-May, it's one of the main reasons the Cardinals are leading the National League Central.

Including back-to-back superb outings in Milwaukee from Todd Wellemeyer and Joel Pineiro, the Cardinals starting staff kept soldiering through a remarkable start to 2008. Three of the five starters entered Sunday with ERAs under 4.00, and Pineiro (4.05) was not far from that standard. Kyle Lohse (4.87) was the only outsider, though his mark includes four earned runs incurred in Colorado -- runs that could become unearned depending on Major League Baseball's ruling to a St. Louis appeal of a call by the official scorer on a play initially ruled an error.

"From the first game off [Adam] Wainwright, we've had a friendly competition," Pineiro said. "We help each other out, we talk about the games, we talk about pitching. When we went out there, nobody gave us a chance in the starting rotation. Nobody thought we were going to be where we are now."

Pineiro said his sinker was particularly effective Saturday, when he allowed two runs in 6 1/3 innings of work.

"All these guys throw good sinkers, and the more I talk to them about it, the more I practice it," Pineiro said. "These guys help me out a lot with that."

Sunday starter Braden Looper (5-1, 3.95), Wellemeyer (3-1, 3.56) and Wainwright (3-1, 2.25) have all made fluid transitions from bullpen assignments to quality starters.

"There really hasn't been anybody that hasn't carried their part of it," Cardinals manager Tony La Russa said.

As for the Lohse situation, a Cardinals team spokesman said Phyllis Merhige, MLB's vice president of club relations, sent an e-mail noting that the matter would likely be reviewed mid-week.

In Thursday's loss to Colorado, a bouncer past third baseman Brendan Ryan sparked a two-out, four-run rally. The Cardinals are challenging the official scorer's decision to change the call from an error (which would have made all of the subsequent runs unearned) to a hit.