ST. LOUIS -- Cole Hamels did not hesitate when Cardinals catcher Yadier Molina sent some choice words in his direction on Saturday night. The veteran Cubs starter strode off the mound and barked back, leading to a swiftly calmed benches clearing in the second inning at Busch Stadium.

There is still plenty of fire in the belly of the 35-year-old Hamels, who felt making this final start would give other teams something else to consider as he heads into free agency for the first time. In the hours leading up to the Cubs' 8-6 win over the Cardinals, Nicholas Castellanos held court with reporters as his own open-market experience looms.

• Box score

"I'm going into it not really expecting anything," Castellanos said. "What I've learned is, when I go in expecting something or really wanting something, then there's room for disappointment or a letdown or whatever. So I'm just going in with an open mind and seeing what comes my way."

What is coming the Cubs' way is an offseason of change.

Hamels and Castellanos -- big-ticket acquisitions ahead of the last two Trade Deadlines, respectively -- are two among a notable pack of impending free agents for the Cubs. The 38-year-old Ben Zobrist is at the end of his contract, as are relievers Steve Cishek, Brandon Kintzler and Pedro Strop. Chicago will also have contract options to sift through.

• Benches clear after Hamels hits Yadi with pitch

All of that is just the tip of the offseason iceberg. The Cubs are currently considering whether to bring back manager Joe Maddon, whose contract expires at the end of this campaign. After missing the playoffs for the first time since 2014, the front office will also be examining the team's core group and factoring in potential trade scenarios to upgrade the roster.

• Maddon, Epstein meeting to discuss future

That has created a sense of unknown for the players in Chicago's clubhouse.

"It's emotional at the end of each year," Cubs third baseman Kris Bryant said. "You know the team is never going to be the exact same the next year. Guys are going to go their own way. Guys are going to retire. And that sucks. You form bonds with these guys. Every single day of the year, you see them. Sometimes you don't want to see them."

Bryant let out a laugh at that last remark.

"You just remember all those good times, times that you're never going to get back," he continued. "That's kind of how I'm looking at everything with Joe or Zo or guys that might be moving on. Yeah, it sucks to think about, but that's just the nature of this game, too."

In the Cubs' penultimate contest of the 2019 campaign, Ian Happ slugged a pair of home runs to lead a four-homer attack from the offense, which was absent Castellanos due to a groin pull that has stalled his pursuit of 60 doubles.

On the mound, Hamels pieced together four shutout innings, piling up eight strikeouts, giving up just two hits and walking none.

“Cole Hamels, that was outstanding. That stuff was classic Cole,” Maddon said. “That's among the best outings he had all season, so he's done a nice little reset, rehab and I was very happy for him.”

Retirement is the furthest thing from Hamels' mind, but he knows other teams might not look favorably at his injury-marred season. A left oblique strain cost Hamels the month of July, and left shoulder fatigue forced him to miss a start last weekend. Hamels could have called it a year, but he opted instead to go up against a St. Louis team trying to secure a National League Central title.

"Trust me, I know I'm healthy. I feel amazing," Hamels said. "But, this is my first time going into free agency. I don't want to put that in the back of teams’ heads of how I finished. I think I'm capable of what I was able to do in the first half. That's who I am."

Hamels spun a 2.98 ERA in his first 17 starts before walking off the mound in Cincinnati on June 28 with the oblique injury. After returning from the injured list in August, the left-hander turned in a 6.39 ERA in nine outings leading up to Saturday's appearance. Four strong innings will not alter the landscape of Hamels' free agency, but peace of mind was surely attained.

It is no secret that the Cubs will be in the market for rotation help this winter, and Hamels still feels he could provide a solution.

“I enjoyed my time here, and I'd like to continue it,” Hamels said. “I do understand what they have to go through, construct, identify. But I would love to be a Cub. And I know, if it's not the case, at least I left it out here.”

And then there is Castellanos, who instantly injected a dose of adrenaline into the Cubs' lineup upon his arrival this summer.

"Everything that you guys saw was just genuine, raw emotion," Castellanos said, "because of how much I wanted to win and I wanted to be in October baseball."

In 51 games with the Cubs, Castellanos churned out 16 homers, 21 doubles, 36 RBIs and 43 runs with a 1.002 OPS. He felt right at home at Wrigley Field, hitting .384 with a 1.162 OPS at the old ballpark. On the year, he had 27 homers, 58 doubles and 100 runs scored, and he became the second player since 1936 to have at least that many two-base hits.

Now, the Scott Boras client will hit free agency ahead of his age-28 season. Going from the 112-loss Tigers to the Cubs brought out the best in the outfielder, who will be looking to harness that same kind of energy in a winning environment in 2020 and beyond.

Would Castellanos like to be back with the Cubs?

"What do you think?" he said.

Yes, he would, but Castellanos also plans on seeing what direction the Cubs' front office takes in the coming months.

"Let's see. Let's see what happens, man," Castellanos said. "I'd say that I'm a pretty observant individual, so I'm going to be as observant as I can and just kind of watch how everything plays out."