Flacco would become the player with the highest salary-cap figure in the NFL in 2017. He is scheduled to count $24.55 million against the cap.
Romo currently owns that title with a $24.7 million cap number, but a source told ESPN's Ed Werder that Romo expects to be released.
That would move Flacco to No. 1, a distinction that will once again stir up the "elite" debate as well as the comparisons to other quarterback contracts. Flacco, who ranked No. 24 in passer rating this past season, has a higher cap figure than Tom Brady ($14 million), a five-time Super Bowl champion; Aaron Rodgers ($20.3 million), a two-time NFL Most Valuable Player; and Drew Brees ($19 million), who threw over 5,000 yards for the fourth time last season.
The Ravens, who currently have less cap space than 27 teams, have 14.6 percent of their salary cap allocated to Flacco. His cap number is more than twice as high as anyone else on the Ravens roster except for cornerback Jimmy Smith ($12.6 million).
At the end of the season, team officials said they need more out of Flacco than last season's production of 20 touchdowns and 15 interceptions.
"We have a quarterback, and he is in that level of compensation, so we need to get him playing at that level," coach John Harbaugh said.
Flacco's cap number doesn't represent the total cash he'll receive this season. The new money he'll make this season is $6 million in base salary and $15 million in deferred signing bonus.
The breakdown of his $24.55 million cap number is $6 million in base salary, $13.8 million in pro-rated signing bonus and $4.75 million in pro-rated option bonus.
Flacco would actually have a higher cap number if not for an extension signed last year, which was designed to flatten out his cap figures. He was originally scheduled to count $31.15 million against the cap in 2017 before signing a three-year, $66 million deal in March.
This marks only the second season in which Flacco has ranked among the top-15 cap numbers. Last season, he had the fourth-highest cap figure at $22.55 million.
Harbaugh was asked earlier this year if he had any concerns that the weight of Flacco's contract puts pressure on the way he plays and affects decision-making in games.
“I sure hope not," Harbaugh said. "I would be surprised if that was the case. I have not heard that theory, but it is interesting. I do not think so, and I would not expect that to be the case. I think you go out there and you play the game to the best of your ability.”