CHICAGO -- The Cubs are hopeful that first baseman Anthony Rizzo will not need to be placed on the injured list for Opening Day, but the team is continuing to take precautions as he works to improve from a nagging back issue.

On Wednesday, the Cubs announced that an MRI exam on Rizzo confirmed rib head inflammation on the left side in the thoracic area, contributing to spasms in his lower back. Manager David Ross said it was premature to speculate that a trip to the IL was looming for the first baseman.

"I think it's still a little too early to make that decision," Ross said. "It's a daily dialogue that we have. We're not going to rush to that decision yet. He's a big part of our lineup, a big part of this team, so I'll rely on him and the training staff and then make that decision."

Rizzo has dealt with back issues on occasion throughout the past six years with the Cubs, so he and the team's training staff have an established plan of attack. Right now, Rizzo is spending his time doing strengthening and stability work indoors, and he's heading to the bullpen to track pitches from Chicago's pitchers.

With a week's worth of game at-bats lost to the setback, Rizzo explained the situation as a risk-reward decision on his part. He wants to use these remaining Summer Camp days to his advantage, and then weigh the risk of staying available, knowing the reward is getting the most out of the upcoming campaign.

"We know how important every game is," Rizzo said of the 60-game regular season. "So for me personally, I'm going to be pushing to get back as fast as I can and take the risk, because the reward of being with the guys and playing alongside of them is worth it for me."

One only needs to look back to September to see an example of Rizzo's determination to stay on the field in the thick of a postseason chase.

On Sept. 15 last year, Rizzo sustained a gruesome right ankle injury in a game against the Pirates, and it seemed likely that he was done for the season. Rizzo, who used a medical scooter and wore a boot in the days immediately following the injury, worked behind the scenes and reached a point where he was cleared to play four days later.

"Listen, this guy has one of the most powerful minds that I’ve been around," Cubs hitting coach Anthony Iapoce said recently. "He can talk himself into anything. Last year, when he did the ankle and him being in the cage when he was going through that process, and talking to himself about how he was going to play that night ... it was just so -- for me as a coach, it was like a monumental moment."

Rizzo took some swings in a live batting-practice workout on Sunday morning, and the initial showing was encouraging for Ross. The manager noted that Rizzo swung and missed without any issues on a few pitches, which is a good test for the back. It was later on after that workout that the first baseman's back spasms flared again.

"I felt good -- just didn't recover the way we'd like it to," Rizzo said. "So it's kind of just get back to what we've been doing inside."

Rizzo noted that he felt much better on Wednesday morning, compared to the past few days. He added that the most frustrating part is that he arrived to Summer Camp in such great physical shape. Over the three-month break, Rizzo worked with quality assurance coach Mike Napoli regularly and shed around 25 pounds.

"You just can't control the flare-ups," Rizzo said.

If the back issue persists to the point that the Cubs need to place Rizzo on the IL, the main backups for first base are catcher Victor Caratini and Kris Bryant. Both got reps at first base during Wednesday's intrasquad game at Wrigley Field. Utility man David Bote has also worked at first base during some of the recent scrimmages.

Even if Rizzo avoids the IL, the Cubs will have 17 consecutive games at the start of the season before reaching the first of six scheduled off-days. Ross will have the designated hitter available to help, and he noted that Bote can slide to third if Bryant is at first. Third-string catcher Josh Phegley is also in a good position to make the Opening Day 30-man roster, which would help Ross with moving Caratini around.

"A lot of these players are used to playing multiple positions and moving around," Ross said. "We've got options all over the place for matchup purposes if we need to move some guys around, if Rizzo is not available to play."

Rizzo plans on doing everything in his power to avoid that scenario.

"We're kind of just getting this calmed down and I'll get back out there as fast as I can," he said. "I've managed through a lot, but we're going to take it day to day. I'd rather miss a couple games early, if necessary, than a big chunk."