Heading into 2022, one thing is certain about the Cubs pitching staff: Kyle Hendricks will be at the forefront of the rotation.

Beyond that, there are a lot of question marks about what form this pitching staff will take.

Adbert Alzolay will probably receive another rotation spot while fellow youngsters Keegan Thompson and Justin Steele are trying to prove they belong as starters in the big leagues.

It’s clear the Cubs will need to acquire at least one bonafide rotation option for 2022 — via trade or free agency — for stability and depth.

But don’t sleep on Alec Mills and what he might be able to contribute to the 2022 starting staff.

After 8.1 shutout innings against the 1st-place White Sox Saturday evening, Mills is now 6-6 with a 4.32 ERA in 2021.

Those numbers are even better in the rotation, as he sports a 3.73 ERA and 1.33 WHIP as a starter. He had a 6.41 ERA and 1.73 WHIP in 12 relief outings to begin the season.

That lines up with the rest of his career: Mills has a 3.92 ERA in 31 starts in the big leagues while pitching to a 5.24 ERA in 25 relief outings.

He routinely flies under the radar as an unassuming pitcher with an average fastball velocity hovering below 90 mph. He doesn’t have quite the same track record as Hendricks, but Mills has still been a reliable contributor in the Cubs rotation the last few years.

“He’s just been as consistent a guy as I’ve had since I’ve been here,” David Ross said. “The things we’ve asked him to do — ups and downs. That’s a really good [White Sox] lineup he just ran through pretty efficiently. He’s definitely a guy that’s proven every time he takes the bump that he gives you a chance to win.

“It’s a nice feeling. You know he’s gonna throw strikes, use both sides of the plate, he can pitch to a scouting report, he can pitch to his strengths. He’s got multiple weapons. He’s a really good pitcher that just is as consistent as we’ve had this year to me.”

After his gem Saturday night, Mills said he knew the White Sox were an aggressive team and liked hitting fastballs. He used that to his advantage, inducing a lot of weak contact with his sinker/2-seam fastball.

He struck out just 3 batters but let his defense work behind him and was efficient. Mills needed just 4 pitches to dispatch Eloy Jiménez over the course of 4 plate appearances (3 groundouts, 1 fly out).

“That’s the art of pitching,” Ross said. “Coming from a catcher’s perspective and a background, you always want to go with your pitcher’s strength first and establishing that. Hitting’s really hard. If your pitcher has real strengths and has real weapons, then you’re gonna err on the side of that.

“There will be times when maybe the game’s on the line that you haven’t shown that you can go to the hitter’s weakness. Maybe you do that, maybe you set guys up. An example I talk about a lot — Jon Lester loved to throw 4-seamers and cutters in to righties. He was going to establish the inside part of the plate. One, it locked him in and his strengths of where his release point would be and where he could throw strikes and felt comfortable. It also sped up the right-handed hitters — they start looking in there.

“Then later in the game, you can throw a 2-seamer away, you could throw a backdoor cutter, you can throw a changeup away. You’ve got guys sped up inside. That’s the cat-and-mouse of what starters go through because they’ve got to get through the lineup multiple times. That’s one thing I thought Millsy did a nice job of Saturday — even when he fell behind, he knew that with his strength with his 2-seamer, there were places in there to go. … He really went to his strengths a lot and he has some deception in that.”

Mills will turn 30 in November, but he still has four years of team control remaining after this season. He joins Patrick Wisdom, Rafael Ortega and Frank Schwindel as other players on the Cubs who have popped onto the scene later in their careers but have demonstrated their value in the big leagues.

“Age is just a number, right?” Mills said. “We’ve been some late bloomers, but at least we’re blooming. At least we’re playing well in a situation in the big leagues and just trying to take every day we can and be happy with where we’re at and just keep producing.”

The Cubs can utilize Mills in a swingman role next season, working in short bursts or multiple innings out of the bullpen and making the occasional start.

Or maybe he pitches well enough down the stretch to prove to the organization once and for all that he belongs in the rotation.