Guards Anthony Edwards (knee) and Donte DiVincenzo (lower leg) suffered injuries in the first half and were forced to leave the game.
Both players were later ruled out for the remainder of the game by the team.
Edwards appeared to hyperextend his knee after defending a shot at the rim by Nuggets forward Cam Johnson.
The 24-year-old went down to the court and needed help to go to the Minnesota locker room.
Edwards, a two-time all-star, played 17 minutes before leaving, collecting five points and three rebounds on 1-of-3 shooting.
During the regular season, he averaged 28.8 points, 5.0 rebounds and 3.7 assists in 60 games.
DiVincenzo, 29, suffered his injury less than two minutes into the game. After missing a three-pointer from the wing, he went to chase his rebound but fell to the ground, held the back of his right calf and was immediately subbed off.
DiVincenzo has been an important piece of Minnesota’s rotation this season. He played and started in all 82 regular-season games, averaging 12.2 points, 4.1 rebounds and 3.8 assists on 37.9 per cent shooting from deep.
He had continued to produce through the first three games in the Timberwolves’ first-round series, shooting 50.0 per cent from deep and averaging 14.3 points per contest.