EDEN PRAIRIE, Minn. (AP) -- Minnesota Vikings quarterback Teddy Bridgewater suffered a "significant" knee injury in practice Tuesday and the team was awaiting tests to determine how long he might be out.

Coach Mike Zimmer confirmed the injury a few hours after an ambulance took Bridgewater from the practice field to a nearby hospital. There is no timetable on how long the third-year quarterback will be out. But when Zimmer was asked if he had any hope of Bridgewater being able to return sometime this season, the coach replied, "I don't know. It doesn't look good right now."

Bridgewater dropped back to pass during a drill, planted his foot and immediately went down. He grabbed his left knee while concerned teammates and athletic trainers huddled around him.

Zimmer called off practice after 25 minutes, and the rest of the team walked off the field while Bridgewater was being attended to. Moments later, a siren-blaring ambulance pulled into the team's Winter Park headquarters, stayed for about 10 minutes and then pulled away with the quarterback in tow, his leg immobilized in an air cast.

"Teddy's such a great kid," Zimmer said. "I love this kid. Our fans love this kid."

Zimmer said the team would release full details when it receives the results of tests done on Bridgewater's leg.

Players were visibly distraught as they exited the field, some hurling expletives into the air. A small group remained behind, huddled around him in prayer as team athletic trainers tried to get him stabilized.

Zimmer tried to straddle a fence in his remarks between being concerned for Bridgewater, one of the most popular players on the team, and not allowing his players to give up on a season that has not even started. He addressed the team in full after practice was called off and said he had also spoken multiple times to Bridgewater's mother.

"We're not going to stick our heads in the sand, we're not going to tuck our (tail between) our legs," Zimmer said. "We're not looking for excuses. We're going to go out and fight like we always do."

If Bridgewater is unable to return in a timely manner, there is little behind him on the depth chart. Shaun Hill is the primary backup, but he's 36 years old and has played only sparingly over the last five years.

"I have confidence in Shaun," Zimmer said. "I think he's played great this preseason. He's been in 2-minute drills. He's done a phenomenal job."

The Vikings were counting on Bridgewater to take some major steps forward after a promising start to his career. He helped lead the Vikings to the NFC North championship last season as more of a game manager, but Zimmer and offensive coordinator Norv Turner have said that they expected him to be much more of a playmaker in 2016.

Bridgewater missed the second preseason game with a sore shoulder, but was very sharp on Sunday against San Diego. He went 12 for 16 for 161 yards and a touchdown in two quarters of work, leaving Vikings players and fans fully confident as the team starts to prepare for the season opener at Tennessee on Sept. 11.

The Vikings host the Los Angeles Rams in their final preseason game Thursday night, though Bridgewater and most of the starters were not expected to play.

Zimmer said he has already had preliminary discussions with general manager Rick Spielman about adding another quarterback if necessary, and he vowed to enter the season with hopes as high as they were before Bridgewater went down.

"This is about the team. This isn't a one-man deal," Zimmer said. "We all feel terrible if it is real significant for Teddy. But this is about the team. We have a good team. ... This is about a team and it's about us trying to figure out ways to win football games.