When the Ravens take the field Thursday morning for their first full-squad practice of training camp, they are expected to be without their starting quarterback.
Joe Flacco is dealing with back discomfort that will likely shut him down for at least the first week of training camp, sources said Wednesday. It's the latest in a suddenly mounting list of injury concerns for the Ravens as they begin preparations for the 2017 season.
According to sources, Flacco, who reported to training camp last week, has been feeling some back discomfort for the past two weeks but it was especially stiff Wednesday, prompting him to get an MRI done.
Team officials are hopeful that his symptoms calm down when he is re-evaluated after a week of rest.
An NFL Network report indicated that Flacco could be sidelined for as long as three to six weeks, but Ravens officials currently have a more optimistic outlook on the situation. The Ravens open the regular season against the Cincinnati Bengals in six weeks.
The Ravens have yet to publicly comment on the injury. Ravens coach John Harbaugh is expected to speak with reporters after Thursday's practice. Flacco, 32, is scheduled to speak to the media after Friday's workout.
The Ravens have only two other quarterbacks on their roster: veteran backup Ryan Mallett and Dustin Vaughan. Even if Flacco is out for a short period, the Ravens might still have to add a quarterback just as another camp arm to get through practices.
Colin Kaepernick, who played under Ravens assistant Greg Roman with the San Francisco 49ers, and former Washington Redskin and Cleveland Brown Robert Griffin III are two of the top quarterbacks available.
Flacco, who is entering his 10th season as the Ravens starter, has missed just six games in his career. He tore the ACL and MCL in his left knee during the 2015 season, ending his streak of 137 consecutive starts.
Flacco returned from the knee injury in time to participate in the first practice of training camp last year. He played all 16 games in 2016, but had one of the most disappointing seasons of his career, averaging 6.42 yards per reception and throwing for 20 touchdowns compared with 15 interceptions.
He didn't use the knee injury as an excuse for his uneven 2016 performance, but Flacco did acknowledge how beneficial it was to have a healthy offseason during which he didn't have to rehabilitate.
The Ravens start training camp with some questions on offense, specifically along the offensive line and at tight end, where they've dealt with injuries.
However, after reporting to the Under Armour Perfomance Center on Wednesday, top returning receiver Mike Wallace expressed confidence in the potential of the offense and cited Flacco as a major reason.
"He's the guy that makes the whole offense work, so just spending more time with him and him being healthy for the whole offseason and being able to work with him even more, it just puts us in a better position and a better place," Wallace said. "Even from day one last year in training camp, he was ready to go. But for him to be healthy and not to have to worry about his knee at all and getting time from day one in [organized team activities] and everything, we all feel a little confident."
The Flacco news comes a day after the Ravens learned that running back Kenneth Dixon will miss the entire 2017 season after knee surgery. The Ravens have also lost tight end Dennis Pitta (hip) and cornerback Tavon Young (knee) to season-ending injuries. Pitta has since been released. Tight end Darren Waller was suspended for the entire season after being found in violation of the NFL's substance-abuse policy.