OWINGS MILLS, Md. -- Baltimore Ravens coach John Harbaugh said it's "up in the air" whether quarterback Joe Flacco will start Sunday because of an injured right hip.

The uncertainty with Flacco goes beyond this critical game against the Cincinnati Bengals. If the Ravens lose to the Bengals, they'll drop to 4-6 and fall essentially three games back of Cincinnati for the AFC's final playoff spot with six weeks remaining. In other words, Baltimore's postseason chances would be extremely slim.

A fourth straight loss could mean the Ravens decide to bench Flacco and start Lamar Jackson, giving the rookie first-round pick the final month and a half to develop. From Flacco's standpoint, Sunday's game might represent his last chance at holding on to his starting job.

It was only a week ago when Harbaugh said Flacco would be the team's starter for now, which was far from a vote of confidence. On Monday, Harbaugh said the decision at starting quarterback will be determined by Flacco's health.

"If Joe can play, he’ll play," Harbaugh said.

If Flacco can play, he'll have a prime opportunity to get his season back on track and perhaps remain Baltimore's starter in 2019.

Over the final seven games, the Ravens will face pass defenses all ranked in the bottom half of the NFL, including five of the six worst in the league (Cleveland, Kansas City, Tampa Bay, Atlanta and Cincinnati). The Bengals are the only defense that's giving up over 300 yards passing per game.

It could prove difficult for the Ravens to move on from Flacco if he finishes strong and leads Baltimore to the playoffs.

This has become the biggest swing game in Flacco's 11-year career.

"We always talk about, when you’re worried about the outcomes of things, and you’re looking too far ahead and worrying about things that aren’t in our control quite yet, you get yourself in trouble," Flacco said before the bye. "It’s tough to do that, but you have to be mentally strong, and just be able to focus on the task at hand and move on."

For now, the question Flacco must answer is whether he can go from walking on crutches last week to starting an NFL game. If Flacco has proved anything during his time in Baltimore, it's never count him out physically.

Flacco has played with a herniated disc (last season), a sprained MCL (end of 2013), a sprained ankle (middle of 2009), a sore throwing shoulder (middle of 2016) and a bruised leg that had 3 inches of swelling (2009 playoffs). He has appeared on the injury report only eight times, and he has missed only three practices during the regular season.

The one time Flacco was sidelined occurred in 2015, when two torn knee ligaments knocked him out of the final six games that season. Still, after suffering that significant knee injury, Flacco finished out the final three plays in that game to set up Justin Tucker's winning field goal.

"He’s one of the toughest guys that you know -- that I’ve played with. Maybe the toughest guy," guard Marshal Yanda said. "You never see him get injured. I mean, you never see him limping around. You never see him on the field showing any signs of weakness. He’s just been a rock for us for more than a decade. I’ve been fortunate, and just it’s awesome to play with a guy like that. I have nothing but respect for him. I love the guy.”

Flacco has led the Ravens to a Super Bowl victory, 15 playoff games and only one losing season. But he's in the midst of another disappointing season, throwing for 12 touchdowns with six interceptions (84.2 passer rating) while struggling to pass the ball downfield.

Baltimore can financially part ways with Flacco for the first time since he signed a three-year extension worth $66.4 million that put him under contract through the 2021 season. The Ravens can create $10.5 million in cap space by cutting Flacco after the season or free up $18.5 million in space by designating him as a post-June 1 cut.

Much will depend on Sunday's game against the Bengals. A win puts the Ravens in the thick of the AFC wild-card race. A loss drops them two games back of Cincinnati (5-4), but it's actually a bigger gap than that considering the Bengals would've swept Baltimore.

At the start of training camp, Flacco was asked whether there would be a point in the season where he would grow sick of repeated questions about Jackson. Flacco's response in late July: "No, I don't, because I think we're going to win and we're not going to hear about it."

Flacco and the Ravens haven't won, and the rumblings about switching to Jackson will only grow louder if Baltimore can't beat Cincinnati.