Nice write-up on him in SI. Talks about his time at Michigan, the start of his time in the Yankees system, and his uncle, former Yankee Paul O'Neill.
From the article:
The two O'Neills approach the game in different ways, however. Paul's best asset was his power at the plate; Michael's is his speed on the basepaths. In three years at Michigan, Michael stole 72 bases -- fourth all-time at the university.
"He's one of those rare players that has technique and speed," says Michigan coach Erik Bakich. "But the scary part is that he's only scratching the surface. I can't wait to see how remarkable he is in a year or two.