Allen agreed in early July to a four-year contract worth $20 million, keeping the nine-year veteran with Memphis.
The Grizzlies announced Monday that they had signed both Allen and Leuer to multiyear deals, and chief executive officer Jason Levien said they are absolutely thrilled to bring back Allen.
The 6-foot-4 Allen scored 10.3 points and had 6.1 rebounds with 2 steals in the playoffs as Memphis reached its first Western Conference final. Allen also received more points than any other player for this season's NBA All-Defensive First team. He finished in the top six in voting for the league's Defensive Player of the Year award each of the past three seasons.