Denver Broncos tight end Joel Dreessen has suffered a setback in his recovery from a knee injury that could cause him to miss the start of the new NFL season.

Dreessen underwent initial surgery on his left knee in May and was believed to be making good progress ahead of the upcoming season, participating in training sessions with the rest of the squad.

However, the 31-year-old was forced to sit out Saturday's intra-squad scrimmage due to pain in his knee and could now be set for a second operation.

The procedure could make him miss the rest of the Broncos' pre-season campaign and could also rule him out of their first NFL match of the season against the Baltimore Ravens on September 5.

Fellow tight end Jacob Tamme is also currently injured, although he is not expected to miss the start of the new season.