MLB.com writer Mark Sheldon said Abbott will wear jersey No. 41, previously worn by Tom Seaver, World Series-winning manager Lou Piniella and Joe Nuxhall.
Reds right-hander Ben Lively (3-3) was charged with five runs and six hits in seven innings in his first loss since May 19. He struck out five and walked three.
The 26-man payroll for the Reds, according to Spotrac.com, was a measly $27,293,743 this week. That was by far the lowest in all of baseball.
The Reds (26-32) have dropped three in a row since a five-game win streak.
The crowd of 44,073 was a regular-season record at Great American Ball Park
This will be Votto's second rehab assignment. He was just 7-for-38 with 21 strikeouts in 45 at-bats during a stint in April.
Reds starter Hunter Greene allowed a run in six innings. He struck out eight.
Greene tossed six innings and allowed just two hits and one run while striking out eight in a no-decision at Fenway Park.