With Mixon set to return to the starting lineup for Sunday's matchup against the Miami Dolphins, the Bengals ruled out backup Giovanni Bernard due to a knee injury.
Bernard, who played well in Mixon's two-game absence, is expected to be sidelined for two to four weeks due to an MCL sprain, the NFL Network reported.
Mixon sat out the past two games after undergoing a procedure to repair a slight meniscus tear in his right knee. He was hurt in Cincinnati's 34-23 victory over Baltimore in Week 2.
Bernard rushed for 69 yards and a pair of touchdowns in last week's 37-36 victory at Atlanta. He had 61 yards rushing and a score on 12 carries in a Week 3 loss at Carolina. Bernard also had nine receptions in the two games.
A second-round draft pick of the Bengals in 2013, Bernard rushed for at least 680 yards in each of his first three seasons. He is a reliable pass-catching threat out of the backfield with 230 receptions in his first five seasons.
Mixon practiced on a limited basis Wednesday and Thursday but was removed from the team's injury report Friday.
Cincinnati's second-round pick in 2017, Mixon rushed for 84 yards on 21 carries against the Ravens after opening the season with 95 yards and a touchdown on 17 rushes in a season-opening win at Indianapolis.
The 6-foot-1, 228-pound Mixon rushed for 626 yards and four touchdowns in addition to catching 30 passes for 287 yards as a rookie.