DENVER — The Chicago Cubs roll into the final month of the regular season firmly in playoff position.

And yet their three-city West Coast trip created complexity for the Cubs’ standing. Those long West Coast series are notoriously challenging trips, but two walk-off losses and getting swept in San Francisco on the heels of sweeping the Angels in Anaheim leave the Cubs feeling they left a couple of winnable games on the field. The Cubs couldn’t complete a sweep of the Colorado Rockies on Sunday, dropping the finale 6-5 on Mickey Moniak’s RBI triple in the bottom of the ninth against Daniel Palencia.

The Cubs (78-59) struggled to get much going against Rockies starter Tanner Gordon, who struck them out a career-high nine times. Cubs left-hander Matthew Boyd experienced some unlucky weak contact that contributed to four runs allowed in six innings.

Ian Happ’s game-tying, three-run home run in the eighth was his first from the right side of the plate since July 19.

“We’ve put ourselves in a good position here,” Happ said. “We would like to win a couple more games on this road trip … that’s tough. The spot we’re in, we have a lead in the wild card, and we want to go after the division. You have to take it one day at a time, as cliché as it is, and we can’t think about the end of September right now.”

The Cubs will get a boost to their depth on Monday when rosters expand to add one pitcher and one position player. They claimed right-hander Aaron Civale off waivers from the White Sox before Sunday’s game and will use him out of the bullpen. Manager Craig Counsell said Civale’s addition helps them solve the “innings puzzle” in September and gives them another starting pitching option if they sustain another injury to the rotation.

The organization is also signing veteran switch-hitter Carlos Santana, a source confirmed to the Tribune, to provide another experienced bat off the bench who brings plus defense at first base. Santana will be eligible for the Cubs’ postseason roster. League rules stipulate a player must be in the organization by 11 a.m. Monday for them to be playoff eligible. The Cubs must make a 40-man roster move to open a spot for Santana.

The Cubs finished 15-14 in August, ending the month with a 5-4 mark on their West Coast trip. Sunday’s loss was doubly disappointing: they missed a chance to sweep the worst team in baseball and failed to make up ground with Milwaukee’s loss to Toronto. The Cubs begin September 6 1/2 games back of the Brewers, two games up on San Diego for the National League’s first wild-card spot and nine games up on the Cincinnati Reds, the closest team to the final wild-card position.

“The goal was to win the division, obviously, and I think that goal is still very possible,” center fielder Pete Crow-Armstrong told the Tribune on Sunday. “But I think just making it there is all you’ve got to do really. I think we are positioned as good as anybody to go make a run, if this is the month that we get hot, then just carrying that into the playoffs with us, and just taking advantage of how we’ve all done so well, just being together and going through these kind of grindy periods together. We’re set up because we got 30 guys to lean on.”

The Cubs survived August despite uneven offensive performances from key hitters and a dip in home runs. That finally started to turn during the road trip.

Seiya Suzuki hit .236 (21-for-89) in the month, and his two-run double in the third inning Sunday represented only his second multi-RBI game in his last 38 games, the first since Aug. 6. Kyle Tucker’s three-hit day Sunday extended his streak of reaching base safely to 10-straight games, hitting .389 (14-for-36) with four doubles, three home runs and eight RBIs in that span. Happ capped a comeback month with a seven-game stretch that saw him deliver a .333 average (8-for-24) with four doubles, two home runs and seven RBIs.

“It’s really easy when you’re looking at the actual numbers to get frustrated and to try to change things and throughout my career, I’ve learned the only thing you can trust every day is a process, like, that’s all you’ve got,” Happ said. “All you have is today, and the ability to go through your routine and live it one pitch at a time. So if I can look at those things, if I can look at the underlying data and be content with the fact that I’m not striking out as much as I have in my career, I’m still walking, I’m hitting it in the air, those are the things that I can control. And if I can be OK with that it should show up over the course of 600, 700 at-bats.

“That’s the only way you can make it through this game without driving yourself completely mad.”

The Cubs need more from other parts of the lineup that had been key contributors during the first half. It likely won’t bode well for the offense if Dansby Swanson and Matt Shaw, whose five home runs each tied Michael Busch for the team lead in August, are their top power producers. Carson Kelly finished August without an extra-base hit in 77 plate appearances (22 games) while Crow-Armstrong tallied only five extra-base hits and five RBIs in 112 plate appearances.

“I’d obviously like to be contributing, so that’s how I’m going to view that is that I’ve got a month left to go make an impact on this ball club,” Crow-Armstrong said. “And, yeah, it’s just another month to enjoy my time in the clubhouse and on the field with these guys. But I’ve got my mind on the playoffs and playing in October, so just finishing this month strong and giving ourselves the best chance at maybe even taking the division, going on some sort of run here.”

The schedule favors the Cubs’ quest for their first postseason appearance since 2020. They have a 99.7% chance of making the playoffs, according to FanGraphs, ahead of a September slate that features only two of eight series against teams that currently possess a winning record.