Acho signed a one-year contract with Chicago in April after four seasons with the Arizona Cardinals. He made 32 starts and appeared in 51 games for Arizona, making 86 tackles, 13 sacks and three interceptions.
Barrow appeared in all 16 games for the Denver Broncos last season as a rookie, making one start. He had eight special teams tackles and one defensive stop.
The Bears will open the season Sunday at home against Green Bay.