Per Wojnarowski, the deal is for three years and $45 million.
Valanciunas declined the $17.6 million option on his contract this offseason, though Wojnarowski reported in June that the veteran center's "primary intention" was returning to Memphis on a long-term contract.
Valanciunas played well for the Grizzlies after being dealt to the team ahead of the trade deadline in the move that sent Marc Gasol to the Toronto Raptors, averaging 19.9 points, 10.7 rebounds and 1.6 blocks in 19 games. The 27-year-old center also shot 54.5 percent from the field for the Grizzlies and 27.8 percent from three.
His ability and willingness to do the dirty work in the paint on both ends of the court should free up young big man Jaren Jackson Jr. and rookie point guard Ja Morant—the team's two future building blocks—to flourish.
And his return solidifies a key position for the team, giving Valanciunas a home for his prime years. Memphis is probably a few seasons away from returning to postseason status, especially after moving on from veteran point guard Mike Conley Jr., but keeping a solid veteran presence like Valanciunas will help keep the team competitive.