With the Cowboys releasing DeMarcus Ware and the Bears releasing Julius Peppers, three of the top four active sack leaders are on the market.
Jared Allen, also a free agent, has 128.5 career sacks, ranking him 12th in NFL history. (Sacks became an official NFL stat in 1982.) Peppers' 119 sacks ranks 17th in history. Ware is two sacks behind Peppers, 18th all-time.
Among the leading sack artists, only John Abraham, who signed a two-year, $4.6 million deal with the Cardinals before the start of the 2013 season, is on a roster. He ranks ninth all-time with 133.5.
Ware was scheduled to make $12.25 million in 2014, which is why the Cowboys released him. Peppers was scheduled to make $13.9 million this coming season.
The Bears already have replaced Peppers, signing Lamarr Houston to a five-year, $35 million contract.
-- Charean Williams