SpaceX’s Dragon V2 capsule (Robyn Beck/AFP, Getty), Sierra Nevada Corporation’s DreamChaser (NASA), the Cygnus cargo ship (NASA), and Boeing’s CST-100 capsule (Boeing/AP).

Boeing said on Thursday that NASA has cut it from the competition to fly cargo and supplies to the International Space Station, a high-stakes contract potentially worth billions that has received widespread attention in the industry.

The decision means there could be as few as three bidders remaining: Sierra Nevada, SpaceX and Orbital ATK. SpaceX and Orbital currently hold the contract to resupply the space station.

The announcement of the award for the next round of contracts was scheduled to happen Thursday. But NASA delayed it again, this time to no later than January, which it said would "allow time to complete a thorough proposal evaluation and selection." It declined to comment further.

Boeing spokeswoman Kelly Kaplan said NASA notified the company of its decision Thursday morning. The company has requested a meeting with NASA to learn more about why it was dropped from the competition, and said it "will determine a path forward after that debrief is completed," she said.

Boeing remains convinced that its CST-100 Starliner capsule "offers the best balance of reliability and value," she said.

Lockheed Martin also submitted a bid, but several news outlets have reported that NASA has also dropped it from the competition. NASA and Lockheed have not confirmed that, however, and in a statement Thursday, a Lockheed spokesperson said that, "we feel that our proposal offers value today through affordable, high-capacity Space Station resupply."

[A new space race emerges as NASA prepares to award contract to ferry supplies to the space station]

While SpaceX and Orbital are the incumbents, both have had their rockets blow up on previous missions in mishaps that destroyed all of the food and supplies that they were bringing to the station. Sierra Nevada has also pushed hard in the competition. It was the last company cut from the bidding to fly astronauts to the station, and has moved aggressively to reconfigure its Dream Chaser vehicle to carry cargo.

The cargo and crew contracts represent a significant shift for NASA, which for years used the shuttle to ferry people and supplies to the space station, the orbiting lab about 200 miles above Earth. The agency is now relying on contractors for that work, a move that allows it to focus on other missions, particularly deep space exploration.