Houston, TX (SportsNetwork.com) - The Houston Rockets recalled guard Nick Johnson from the NBA Development League on Sunday with reports that center Dwight Howard could be sidelined for a few weeks.

ESPN on Sunday cited sources as saying Howard's lingering knee problems could keep him out for a month, possibly longer.

Howard, who also suffered an ankle injury in a Jan. 23 game against Phoenix, has missed the last four games. He also missed 11 games in November and early December because of knee soreness.

In 32 games this season, Howard is averaging 16.3 points and 11.0 rebounds.

The Rockets apparently avoided another injury Saturday night, as leading scorer James Harden suffered a bruised knee in the first half against Detroit. He returned to the contest in the second half of the 114-101 setback.

Johnson, who was assigned to the team's D-League affiliate in Rio Grande Valley on Nov. 18, has appeared in three games for the Rockets this season.