Worilds and the Steelers continue to negotiate on a long-term contract, the source said.
The transition tag for linebackers in 2014 is $9.754 million, about $2 million less than what Worilds would have made if he had been designated as Pittsburgh's franchise player.
Worilds put it all together in 2013 after getting a chance to start on a regular basis for the first time since the Steelers made him a second-round pick in the 2010 draft. He led the Steelers with a career-high eight sacks and finished second on the team with 29 quarterback pressures. He lost his starting job at right outside linebacker to Jarvis Jones after the first game but reclaimed it once the rookie struggled to adapt to the speed of the NFL game.
Worilds blossomed when he moved to left outside linebacker following a calf injury to LaMarr Woodley.
Even after Woodley, the highest-paid defensive player in franchise history, returned from the calf injury that ultimately ended his season, the Steelers stuck with Worilds at left outside linebacker, moving Woodley to the other side.
Worilds, who turned 26 on Monday, couldn't have picked a better time for a breakout season. The Steelers opted not to sign him to a long-term deal before the final year of his contract, putting him in position to cash in after playing out his rookie deal in Pittsburgh.
ESPN.com Steelers reporter Scott Brown contributed to this report.