The 26-year-old is in the process of recovering from a partial tear in his left patella tendon. The injury forced him to withdraw from the U.S. Open last summer and forced him out of Spain's Davis Cup semifinal.
Nadal has not played competitive tennis since he lost in the second round to unknown Lukas Rosol at Wimbledon last June. The shockingly early exit was the Spaniard's worst finish at the All England Club since 2005, and it raised questions about his health.
Knee problems forced Nadal to withdraw against Murray in the semifinals of the 2012 Sony Ericsson Open in Miami last March.
The Abu Dhabi tournament this December runs from Dec. 27 to Dec. 29 and will provide Nadal with an opportunity to test his knee before January's Australian Open Grand Slam.
Since bursting onto the tennis scene in 2005, Nadal has only missed three major tournaments, including last August-September's 2012 U.S. Open.
The 11-time Grand Slam champion will try to bounce back in 2013 as he attempts to chase down Roger Federer, Djokovic and Murray, who are all staring down at him atop the ATP World rankings.
The world No. 4 boasts a 42-6 singles record in 2012 and has won four singles titles this year.
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