Sizemore has played in just 71 games this season, due to a pair of right knee bruises and surgery to correct a sports hernia. The club sees no benefit in playing Sizemore at this point, with the team eliminated from postseason contention.
"That's the way we're looking at it," general manager Chris Antonetti said. "We're just taking a cautious approach. If we were a game behind the Tigers, it'd probably be a different story."
Though the 29-year-old has not played since Thursday, Antonetti stressed that Sizemore did not aggravate any of his injuries.
Sizemore, who made three trips to the disabled list, hit .224 with 10 home runs and 32 RBIs this season. Sizemore has played in just 210 games over the past three seasons after playing no fewer than 157 in each of the four previous years.