The top defenseman left on the free-agent market is Tampa Bay-bound.
The agreement comes hours after former Predators star Ryan Suter went to Minnesota.
Carle's deal is worth an average of $5.5 million per year, a source told ESPN.com.
Carle, 27, tied for 20th in NHL scoring among defensemen with 38 points (4 goals, 34 assists) this past season in Philadelphia.
It's a second tour of duty for Carle with Tampa Bay. He played 12 games for the Lightning in 2008-09 before getting dealt to Philadelphia in a trade that also featured Steve Downie.