The 26-year-old Colombian, who joined Pramac Racing in 2014, suffered a left-shoulder dislocation during a dirt-track training session. Dirt training during the off season is popular among World Championship riders, and MotoGP Champions like Valentino Rossi and Marc Marquez have also sustained injuries this way.Hernandez’s exams showed microfractures without any lesion to ligaments and tendons, and Pramac Racing says recovery times are estimated in three weeks.The injury will keep Hernandez from participating in the February 4-7 preseason tests. Pramac Racing confirms that Ducati’s official MotoGP test rider Michele Pirro will substitute for Hernandez on the GP14.2 Desmosedici prototype. Hernandez is expected to participate in the second pre-season test at Sepang Feb. 23-26Hernandez joined the premier-class in 2012 with Avintia Blusens (CRT), and made his first appearance on the Pramac Ducati in 2013 while riding as a replacement for the injured Ben Spies at Aragon.When Spies departed with MotoGP following 2013 due to injury, his empty seat was quickly filled by Hernandez. Throughout 2014 MotoGP, Hernandez piloted a Desmosdeici GP13 factory bike, but will use the updated GP14.2 in 2015. His first ride on the GP14.2 was at the traditional post-season tests in Valencia following the 2014 MotoGP season finale.