Lions third-string quarterback Kellen Moore threw two touchdown passes in a 23-0 win over Buffalo on Thursday night in which Bills rookie receiver Sammy Watkins reinjured his ribs.
The first-round pick did not return after being struck in the left side by linebacker Ashlee Palmer on Buffalo's second drive.
Moore hit Jeremy Ross for a 1-yard touchdown and Corey Fuller for a 25-yard score at the end of the second quarter. The Lions' defense combined for four sacks and three interceptions.
Detroit (3-1) rested most of its starters, including quarterback Drew Stafford, receiver Calvin Johnson and defensive tackle Ndamukong Suh.
Buffalo (1-4) continued to sputter on offense and could now be without Watkins for its opener at Chicago on Sept. 7. Watkins did not play against Tampa Bay last Saturday after bruising his ribs a week earlier at Pittsburgh.