CHICAGO -- As the Cubs’ season hits a critical stage, manager David Ross has continued to pull different levers in an effort to get his offense functioning consistently. What was a steady front four for two months has been rearranged, while playing time has shifted at positions around the diamond.

“I’m trying to continue to form the lineup in a way that gets us the most runs,” Ross said.

Roughly 350 miles west of Wrigley Field, where the Cubs picked up a convincing 11-3 win over the Pirates after a 1-hour, 10-minute rain delay on Tuesday night, another lever was pulled from afar. At Principal Park in Des Moines, Iowa, center fielder Cody Bellinger began a Minor League rehab assignment playing first base, revealing more of Ross’ current thinking.

While Ross will not allow himself to veer from the each-game-is-important mantra, the Cubs’ front office is in a holding pattern on how to handle the Trade Deadline. The opportunity at hand consists of six games in a nine-game span against the National League Central-leading Pirates, and now Chicago sits 5 1/2 games back.

Each win is precious right now for the North Siders, and Ross has to weigh every roster move with that in mind. Not all of the manager’s lineup iterations or bullpen decisions have panned out, but there has been no shortage of experimentation of late to squeeze out as much juice as possible.

“I'm sure this season's been stressful on him,” said Cubs starter Jameson Taillon, who yielded three runs over six innings in the win. “He's trying to put the magic pieces together. And I appreciate that. I've seen what he's been doing behind the scenes, and I know he's rooting for us and pulling for us. But at the end of the day, I think sometimes it just comes down to us just playing better.”

One player who has been doing that lately has been outfielder Mike Tauchman, who has filled in admirably as Chicago’s center fielder with Bellinger on the injured list due to a left knee issue. Tuesday marked Tauchman’s third start in a row as the leadoff man, and he collected two hits with a walk.

Tauchman’s free pass in the first inning -- his 13th in 78 plate appearances to help boost his on-base percentage to .403 through 22 games -- set the table for Ian Happ to later deliver a three-run homer. That ended a drought of 144 plate appearances without a blast for the Cubs' left fielder.

“That was a great swing by Ian,” Tauchman said.

And this brings things back to Bellinger.

Happ is entrenched in left and has been a steady on-base machine this season, even with a drop in power. Right fielder Seiya Suzuki is locked in, as well, and has shown signs of life lately (including a hit and a walk Tuesday). In center, Ross has been impressed with Tauchman’s defense, along with his plate discipline.

Bellinger has ample experience at first base in his MLB career (262 games, in fact) and had three at-bats in his initial rehab game while playing on the infield for the I-Cubs on Tuesday night. Ross cited the combination of Tauchman’s play, the nature of Bellinger’s injury and the offensive production at first as reasons to explore this scenario. There is also the designated hitter slot to make the puzzle pieces fit.

“There's a number of thoughts there,” Ross said. “I’m just trying to find the best lineup whenever Belli gets back. He's pretty darn good at first base, and has been. Just having another option over there makes some sense.”

Entering Tuesday, the Cubs’ first basemen had collectively hit .239 with a .699 OPS (ranked 21st in the Majors). Trey Mancini (.845 OPS going into the day) has been the most productive while playing that position, while rookie Matt Mervis has not matched his knack for hard contact with results.

“It’s just a young guy still finding his way in the Major Leagues,” Ross said. “I've thought there's been some good at-bats as of late.”

That included Tuesday night, when Mervis connected for a 109-mph, go-ahead RBI single in the sixth inning. It was one knock within a 14-hit onslaught that was punctuated by a three-run homer in the eighth inning off the bat of Christopher Morel. In May, the Cubs pulled the levers to promote both Mervis and Morel from Triple-A to help the lineup.

Ross has not stopped trying to find the right formula and -- for at least one night -- the offense responded with an all-around outpouring. The lineup should look a little deeper once Bellinger returns, whether at first or back in center.

“I know that the group's excited to get Cody back,” Tauchman said.