PITTSBURGH -- Anthony Rizzo showed recently that injury timetables can sometimes be thrown out the window. Even so, with only five games remaining following Tuesday's series opener against the Pirates, Cubs third baseman Kris Bryant has likely taken his final at-bat of the regular season.

Prior to Tuesday's tilt at PNC Park, the Cubs announced that an MRI exam confirmed that Bryant sustained a moderate right ankle sprain during Sunday's 3-2 loss to the Cardinals. Bryant injured his ankle after slipping on first base while trying to beat out the back end of a double play in the third inning.

"That's definitely a day-by-day thing," Cubs manager Joe Maddon said on Tuesday. "I was with him getting on the bus, and still you could tell how much it's bothering him still. We'll just wait it out and see how it plays out. Everybody's different, so however he feels and talking to the trainers, we'll try to make our best guess with it."

X-rays taken on Bryant's ankle after Sunday's game came back negative for any structural damage. The Cubs said the third baseman will be treated and assessed daily.

"Kind of just a freak injury there. We're doing all we can to make it feel better," said Bryant, who added that one positive was that the setback did not impact the right knee that has bothered him at times this season. "My spirits are up, but it wasn't great when it happened, that's for sure."

It was similar to Rizzo's right ankle sprain on Sept. 15, when the first baseman rolled the foot while fielding a bunt in a game against the Pirates at Wrigley Field. Rizzo was thought to be at risk of missing the rest of the season, but he returned to the starting lineup by Thursday and played in all four games of the Cubs' series against St. Louis.

That was an unusually swift return for Rizzo that was fueled by Chicago still being in the hunt for the National League Central crown at the time. Entering Tuesday, the Cubs were eliminated from the Central race and sat four games back of the second NL Wild Card spot (currently held by the Brewers) with six games to go.

In 147 games played this season, Bryant has hit .283/.382/.521 with 31 home runs, 35 doubles, 77 RBIs and 108 runs scored. The former NL Rookie of the Year (2015) and MVP ('16) entered Tuesday's action with a 134 wRC+ and was ranked 10th in the NL in WAR (4.9 per FanGraphs).

Bryant said he plans on trying to return before the season ends.

"We still have a chance here," Bryant said. "I know everybody here is believing that. I'm believing it and I want to do everything I can to get back out there and feel like I can help the team. That's what we're going to do, and it starts today."

Worth noting

• Shortstop Javier Báez (hairline fracture in left thumb) went through some defensive work on Tuesday with third-base coach and infield instructor Brian Butterfield. Catching the ball without discomfort has been the last hurdle for the shortstop.

"That was Butter's biggest concern," Maddon said. "Right now, he's still not comfortable catching the ball."

• MLB issued a one-game suspension and undisclosed fine on Tuesday to Cubs bench coach Mark Loretta for "inappropriate conduct" following a replay review during Saturday's game against the Cardinals. At one point during the review, Loretta put on the umpires' headset. Quality assurance coach Chris Denorfia served as Maddon's bench coach on Tuesday.

"Yeah, we had a little bit of a security breach," Maddon quipped. "I thought he was near the headphones and picked up on the conversation -- not know he actually put on the headphones, which is kind of interesting. It's kind of like when your kid does something that's a little naughty, but you're kind of proud of it."

• Left-hander Cole Hamels (left shoulder fatigue) threw 20 pitches in a bullpen session on Tuesday in Pittsburgh. Maddon said the mound workout went well and the Cubs will monitor how Hamels feels on Wednesday, but it remains undetermined if the veteran will start again this season.