Thielen, whose overtime reception set up the Vikings' game-winning touchdown during a 26-20 victory over the New Orleans Saints in Sunday's NFC wild-card game, was on the field with the team for the beginning of the workout.
Thielen was added to Minnesota's official injury report after practice, indicating that he was hurt during Wednesday's session. According to ESPN, the injury isn't expected to impact his availability for Saturday's NFC divisional game against the San Francisco 49ers.
The sixth-year wideout wasn't listed on the Vikings' injury report Tuesday. According to ESPN, his official status for Saturday's matchup will be determined on the final injury report Thursday.
Thielen, a two-time Pro Bowl selection, was sidelined for close to half of the regular season because of a hamstring injury. He recorded seven catches for 129 yards in the Vikings' win over the Saints last week.
Minnesota was also without safety Jayron Kearse and nickel cornerback Mackensie Alexander on Wednesday.