Kendrick, a 31-year-old ranked No. 105 in the world, tested positive for the stimulant Methylhexaneamine during the French Open. He admitted taking the substance but said it was in a capsule he took to fight jet lag and he wasn't seeking a performance advantage.
Kendrick lost his first-round match in Paris.
The International Tennis Federation accepted Kendrick's explanation but said a player is responsible for any substance he consumes. Kendrick will be banned from competition until May 21, 2012.
Kendrick has been ranked as high as 69th in his career. A professional since 2000, he's never won an ATP tournament and never advanced beyond the second round of a Grand Slam event.