Cashman got hurt on the second landing attempt after being successful the first time, according to John Harper of the New York Daily News.
Harper also noted that the people who were attending to Cashman believe that the Yankees general manager broke his ankle and provided some details of how it looks.
And finally, Harper got a quote from Cashman about the ankle injury and provided a picture of him being attended to on the ground.
One of the advantages to being in the front office of a sports franchise is that you can get away with certain things your players can't. There is specific language written into player contracts that prevents them from taking unnecessary risks to ensure they stay healthy.
There was a time, back in 2002, when former San Francisco Giants second baseman Jeff Kent broke his wrist while, as he claimed, washing his car. As evidenced in this Hardball Times article, some say that he was actually attempting to do stunts on a motorcycle and didn't have much luck:
He brushed himself off and moved along, and told everyone not to tell anyone what they saw. You damn well better believe he didn’t [sic] anyone to know what he’d just done. It was against his contract with the Giants to do motorcycle stunts and if he injured himself doing one, he could lose a good chunk of cash.
Cashman doesn't have to deal with any legal ramifications from the Yankees, just the sting of a wounded ego. Though he also deserves credit for not only landing one jump, but having the guts to go back up and try it again.
Even though Cashman could take a ribbing from some coworkers, assuming nothing is seriously wrong after getting a full examination, he is braver than most people in his position.