SURPRISE, Ariz. -- It’s no secret the Cubs’ fifth spot in the rotation is up for grabs this spring, and the team is hoping the competition takes care of itself.

Adbert Alzolay, Tyler Chatwood, Alec Mills and Colin Rea are each vying for a spot in the rotation, and the early results from one of many roster battles have been exactly what the Cubs had hoped. Each has shown a glimpse of what they could bring to the table at the back end of the starting five.

Now that each pitcher competing has made one appearance to get in a rhythm, the next wave of the competition begins, and the execution of pitches will play a major role in each standing out.

“I think everybody here wants to beat guys at their best. Obviously, competition is always good and it brings out the best in people. I think it’s fun,” Mills said. “That’s why we play this game. That’s why we love what we do. Everybody loves to compete. Go out there every day and let them make the tough decision."

“I want them to be themselves. I want them to pitch their game, establish who they are. Show me who they are, and each guy has done that,” Cubs manager David Ross said. “Chatwood has done great, Millsy has done great. Alzolay continues to develop and make his mark. I think all these guys are making a good imprint and seem to have come into camp on a mission and ready.”

Chatwood is currently the front-runner to be the Cubs’ fifth starter and showed at times last season that he could be a weapon on the Cubs staff when he’s locked in. He posted a 2.84 ERA after the All-Star break in 2019.

The next few weeks will not only be pivotal in deciding the team’s fifth starter, but will likely determine a few open spots in the bullpen. With Thursday’s news of Brad Wieck undergoing a heart procedure, there may also be an additional spot in the bullpen available, should Wieck not be ready by Opening Day on March 26.

“That fifth spot is open, but there’s also some spots in the bullpen that are available for guys to slide into as the long [reliever] or whatever, so that will all play out in front of us,” Ross said.

Rea -- who allowed four runs on two hits in a one-inning start during the Cubs’ 13-1 loss to the Rangers on Thursday -- has pitched in relief just once over his 26 Major League appearances.

Chatwood and Mills have the most experience working both in the rotation and out of the bullpen. Alzolay made two appearances in relief for the Cubs in 2019, in addition to his two starts.

Mills is also one of three Cubs pitchers out of Minor League options, which may work in his favor as the team looks for a potential swingman in the bullpen. The 28-year-old right-hander went 1-0 with a 2.75 ERA in nine appearances (four starts) last season.

"[For me] it’s confidence. Knowing I can do it at this level. I’ve had success before, but more success is always better,” Mills said. “The little sample size I had, I took into the winter knowing I can and then going into the offseason that I would be competing for a job this year.”