There's already some video from this online - Fox Sports Arizona has a write-up on Hahn's visit to the team - but I think it's worth watching in its entirety. If you're not aware of the story, Hahn was a promising baseball player who had already been selected in the draft out of high-school, the Padres picking him in the 26th round. But he opted to go to college instead, had just started playing for Arizona State, when he suffered a freak accident sliding into second-base, which left him with a fractured vertebrae in his spine, and paralyzed from the waist down.
However, his unbeatable spirit and determination, despite the crappy hand dealt Hahn by fate, made an impact on the Diamondbacks, and they picked him with their 34th-round selection in the recent draft (Hahn wore #34 at ASU). He's currently completing his business degree, but when that's done, the Diamondbacks have basically offered him a spot with the team, in whichever department he wants. It's a remarkable story, which reflects well on the team, but it's no less than Hahn deserves.
Said Derrick Hall at the time of the draft, "It was a very emotional selection for us to make. When Ray Montgomery and his staff came up with the idea and presented it to me, it was a no-brainer. It's not about us. It's really about Cory and his family. I was able to spend time with them right after the injury in his hospital room and he's a wonderful kid. We want to make this permanent. We don't want this to just be about the selection and him being a draft pick, but about him working in full-time employment with the Diamondbacks and hopefully we'll make that come to fruition for he and his family here soon."