Allen emerged as one of the league's premier perimeter defenders in his first season with Memphis, averaging 1.79 steals as well as helping the Grizzlies pace the NBA in steals and forced turnovers. Allen was subsequently named to the 2010–11 NBA All-Defensive Second Team, marking his first and the Grizzlies' first selection to an All-Defensive Team, and finished fourth in the voting for Defensive Player of the Year. He averaged 4.14 steals per 48 minutes, the highest rate by an NBA player since Nate McMillan in 1993–94. Allen averaged 8.9 points, 2.7 rebounds, and 1.4 assists on .510 shooting in 20.8 minutes in 72 games (31 starts). He went on to help the Grizzlies advance to the Western Conference Semifinals for the first time in the history of the franchise.