The Steelers and Antonio Brown are making significant progress towards a big-money extension, sources tell Ian Rapoport of NFL.com (on Twitter). The goal is for the deal to be completed by March 9th. 
If the two sides can agree to terms before the start of free agency, the Steelers will have a better idea of their spending room before dollars start flying.
A new deal for Brown will presumably reset the market for wide receivers, even though it would be an extension one year prior to Brown’s potential entry into free agency. The 28-year-old (29 in July) is the NFL’s best receiver and coming off of his third consecutive first-team All-Pro selection. He has matched or exceeded 100 catches, 1,200 yards and eight touchdowns in each of the past four seasons. Teams have asked about acquiring Brown via trade, but the Steelers have firmly rejected all overtures.
Currently, Julio Jones leads all wide receivers in terms of total contract value ($71.25MM overall), per-year average ($14.25MM per year), and total guaranteed cash ($35.5MM). After him, Demaryius Thomas and Dez Bryant are tied or roughly tied in those categories, with Thomas holding a slight edge in total guaranteed money.
Brown is currently signed through 2017 with a cap charge of roughly $13.6MM.
The guy becomes more of a showboat every year. He has an excellent case for the biggest WR contract in NFL history though, in terms of total numbers, guaranteed money, and yearly.