Green left Sunday's game against the Atlanta Falcons in the first quarter after aggravating the injury and did not return. He originally injured his toe last week and missed practice Thursday, though he returned to practice Friday.
Bengals coach Marvin Lewis hasn't said how long Green might be out.
Green had six receptions for 131 yards in Week 1, including a 77-yard touchdown catch that gave Cincinnati the win over the Baltimore Ravens. He had 98 catches for 1,426 yards and 11 touchdowns in 2013.
The Bengals defeated the Falcons 24-10 on Sunday. They host the Tennessee Titans this Sunday.
- Ben Estes