ST. LOUIS — Cubs manager Joe Maddon started August with several new toys to play with in his lineup and bullpen.

But even with Nick Castellanos and Tony Kemp making their debuts in the starting lineup and holdover ace Jon Lester starting the new month on the mound against the Cardinals, the task down the stretch looked a lot like the Cubs’ labor the first four months.

After an 8-0 loss Thursday, they are one game behind the Cardinals in the National League Central.

And the only thing Maddon knew for sure was that there will be no crying in baseball the rest of the way as the division race and the summer get even hotter with the Cubs’ new-look roster locked into place.

Castellanos, whose debut included a sixth-inning single that broke up Cardinal right-hander Jack Flaherty’s no-hit bid, figures to play almost every day in right or left.

If that means less playing time or role changes for struggling Albert Almora, newly recalled Ian Happ or even streaky Kyle Schwarber, Maddon has a message for any complainers:

“It’s big-boy time.”

The Cubs still have the worst road record in the NL as they left St. Louis on another down beat with their 10th consecutive winless series.

They still have the second-best home record in the league as they head to Wrigley Field for another three-game showdown with the Brewers.

And almost everything in between was in play for the stretch drive in the tightest division race in the majors.

“Right now we’ve just got to put out there what we consider the right thing to do,” Maddon said of the daily task during this final sprint as he gets to know his two new hitters, as well as relievers David Phelps and Derek Holland, who also were acquired in recent days.

“I can’t be as aware, in a sense, as I was last year, just giving guys plate appearances and at-bats developmentally speaking. We have two months to really put our best foot forward. I will move guys in and out, but I don’t feel as compelled to do it as I maybe felt last year.”

Among the things at stake down the stretch are the viability of the competitive window the front office believes it has built to this point, as well as Maddon’s job.

As he embarks on the final two months, the Cubs had eight players on the roster who weren’t there on Opening Day, including five added in recent weeks (including closer Craig Kimbrel).

“I haven’t quite discussed my role, but to be quite blunt, I don’t care,” said Kemp, who started at second base. “I’m just here to help in any way possible, whether that will be off the bench of if they want me to serve water to the guys. I’ll do whatever they need.”

Kemp is expected to play a platoon/bench role. Castellanos is expected to play every day, pushing Jason Heyward from right field to center field on a more regular basis and turning Almora and possibly Happ into part-time players and potential late-inning defensive guys for now.

Castellanos, who is especially effective against left-handers might even find some at-bats leading off against favorable matchups. He batted second Thursday.

The Cubs’ leadoff numbers in July, with Schwarber getting most of those starts, were terrible, ranking last in the majors in average (.152), on-base percentage (.222) and slugging (.323). The strikeout rate was a whopping 30.6 percent, 27th-worst in MLB.

Heyward went 2-for-5 from the leadoff spot Wednesday and was there again Thursday, going 0-for-3.

Castellanos’ thoughts on batting leadoff?

“I don’t care,” he said. “I’m not a very high-maintenance kind of guy. If I’ve got a glove and a bat, I’m ready. Leadoff, third, fourth, ninth, whatever.”

Big-boy answer. Big-boy time.