According to ESPN.com's Jeremy Fowler, Bell said he won't sign an extension that nets him any less than $14.5 million per season.
That is the value of the franchise tag Pittsburgh placed on him for 2018; however, he has yet to sign the franchise tender.
Bell has not reported to mandatory minicamp, and it is widely expected that he will sit out minicamp, training camp and the preseason unless a deal is reached. He did the same while playing under the franchise tag last season, and it didn't appear to negatively impact his play.
The 26-year-old was selected to the Pro Bowl for the third time and named a First-Team All-Pro for the second time. He finished the 2017 campaign with 1,291 rushing yards and nine touchdowns to go along with 85 receptions for 655 yards and two scores.
However, Bell's 4.0 yards per carry was his worst mark since his rookie season in 2013.
Bell will have the NFL's highest cap hit among running backs in 2018 if he signs his tender, and the only other back to top $9 million is Jerick McKinnon of the San Francisco 49ers at $10.5 million, per Spotrac.
Devonta Freeman of the Atlanta Falcons has the largest total salary for a running back after he signed a five-year, $41.25 million extension in 2017.