Thielen got hurt after scoring a touchdown in the first quarter against the Lions in Week 7, as he pulled his hamstring.
The wide receiver missed Week 8, and tried coming back against the Chiefs last Sunday but still wasn't 100 percent. He's now listed as doubtful for next Sunday's matchup against the Cowboys.
This is a really rough blow for Thielen and Minnesota, as the sixth-year receiver is having a nice season, averaging 14.5 yards-per-catch and scoring six touchdowns.
Minnesota had a nice four-game win streak before it was snapped in a close fight against Kansas City last Sunday. But the next few games on their schedule are tough as they'll have to face teams like Dallas, Seattle and Detroit.
They're currently second in the NFC North and project to make the playoffs, but that could quickly change with a few crucial losses. Thielen's absence could be harsh on their passing game unless Kirk Cousins really steps up his game.