St. Brown secured all eight targets for 112 yards and a touchdown in the Lions' 31-29 win over the Vikings on Sunday.
St. Brown (quadriceps) practiced fully Wednesday.
Coach Dan Campbell said Monday that St. Brown (lower leg) "will be good" and has a soft-tissue injury, Richard Silva of The Detroit News reports.
Initial indications are that St. Brown dealt with a contusion and cramping during Sunday's loss to the Buccaneers, Adam Schefter of ESPN reports.
St. Brown, who briefly left Sunday's loss to the Buccaneers, appears to be dealing with a lower-body issue, Kyle Meinke of mlive.com reports.
St. Brown had 11 catches for 119 yards on 19 targets in Sunday's 20-16 loss to the Buccaneers.
St. Brown isn't in line to play in Saturday's preseason game at Kansas City, PJ Green of Fox 4 KC reports.
St. Brown isn't suited up ahead of Thursday's preseason contest at the Giants, Justin Rogers of DetroitFootball.net reports.
St. Brown and the Lions reached agreement Tuesday on a four-year extension, Ian Rapoport of NFL Network reports.
St. Brown is discussing an extension with the Lions, Kyle Meinke of MLive.com reports.