Thielen (hamstring) said after Sunday's 36-22 win over the Raiders that he will undergo an MRI on Monday, David Newton of ESPN.com reports.
Thielen was forced out of Sunday's win shortly after connecting with new starting quarterback Andy Dalton on a 31-yard touchdown in the first half, and he was subsequently unable to retake the field. He finished with three catches for 40 yards and one score. The results of Thielen's MRI could help clear up his availability for Week 4 against the Bears.