Bauer, who's one of the favorites to win the NL Cy Young, could also pitch on short rest Sunday if the Reds haven't secured a playoff spot by the final day of the 2020 regular season.
The Reds contemplated starting Bauer on three days' rest for the season's duration in early July. However, that idea never materialized even though the former All-Star said he wanted to market himself as a starter who will pitch every four days before entering free agency.
Bauer has only pitched twice in his career on three days' rest. Opponents have a .928 OPS against him in those two games.
The 29-year-old has enjoyed a stellar 2020 campaign. He's posted a 1.80 ERA with a career-best 12.2 K/9 across 10 starts for the Reds.
Cincinnati enters Tuesday's action holding the No. 7 seed in the NL. The club's magic number to clinch a playoff spot is six.