Safety Andrew Sendejo, meanwhile, participated in a portion of practice and appears on track to start Sunday despite a concussion he suffered in the divisional round of the playoffs. Zimmer said Sendejo will "be fine."
Thielen's injury apparently occurred during the Vikings' 29-24 victory Sunday over the New Orleans Saints. Coach Mike Zimmer did not mention it while speaking with reporters Wednesday morning, and Thielen did not comment.
There is no fear at this point that Thielen will miss Sunday's NFC Championship Game against the Philadelphia Eagles. But it is unclear how much he'll practice, if at all, this week.
Sendejo remains in the NFL's concussion protocol, but has advanced through enough stages to qualify for partial practice participation and was officially listed as limited on Wednesday. He won't officially be cleared until later this week, when he visits with an independent neurologist, but the Vikings appear confident he will be ready.
Sendejo's return would put the Vikings' top-ranked defense at nearly 100 percent entering Sunday's game. The only question mark is backup defensive lineman Shamar Stephen, who is dealing with a knee injury.
Thielen played 95 percent of the Vikings' offensive snaps (77 of 81) against the Saints. He did not join the team's end zone celebration after Stefon Diggs' game-winning 61-yard touchdown, he said Sunday, because he couldn't move from his spot on the other side of the field.
"I was in shock," Thielen said.
Thielen caught six passes for 74 yards in the game. During the regular season, he caught 91 passes for 1,276 yards and four touchdowns.
Sendejo suffered his concussion after absorbing a block from Saints receiver Michael Thomas in the third quarter. Sendejo, who had intercepted Saints quarterback Drew Brees in the second quarter, walked off the field under his own power.
Video of the Vikings' wild postgame celebration showed Sendejo greeting players as they ran toward the locker room.