Multiple sources told ESPN that an MRI revealed Dulcich suffered an injury to his right hamstring, the same hamstring that cost him seven games as a rookie last season.
Dulcich, who had two receptions for 22 yards Sunday, was one of the players Broncos coach Sean Payton had expressed high hopes for in the team's offense. Payton said Dulcich could play the "Joker" at times -- an offensive role filled by players such as Reggie Bush and Alvin Kamara during Payton's time as New Orleans Saints coach.
Dulcich, who was seen grabbing his right hamstring after running a downfield pass route in Sunday's game, did not play in the second half of the Broncos' 17-16 loss to the Las Vegas Raiders. His injury compounds an early-season problem for the Broncos, who have lost several players who add speed and explosiveness to the offense.
Wide receiver KJ Hamler was diagnosed with a heart condition before training camp, is being treated with medication and is not on the roster. Wide receiver Tim Patrick suffered a season-ending Achilles tendon injury in the first week of training camp, and wide receiver Jerry Jeudy did not play in the opener because of a hamstring injury.
As a result, the Raiders gave the Broncos a steady diet of zone coverages Sunday, and Denver's longest pass play was a 21-yard catch-and-run by Brandon Johnson. The Broncos had just two pass plays over 15 yards in the game.
Quarterback Russell Wilson was efficient -- 27-of-34 passing for 177 yards and two touchdowns -- but the Broncos averaged 6.6 yards per completion.
Seventeen of Wilson's completions Sunday went to tight ends or running backs, so Dulcich's absence will be felt, given he was the big-play potential at tight end. The Broncos are expected to take a conservative approach in Dulcich's return with him having injured the same hamstring multiple times in the past year. The third-round draft selection missed the first five games of his rookie season and also was sidelined for Denver's final two games.
Dulcich, 23, finished third on the team in catches last season with 33 and was one of four Broncos players who had at least two receiving touchdowns. Fourth-year veteran tight end Adam Trautman had five catches Sunday and figures to be Denver's primary tight end during Dulcich's absence.