Alonso, who is 6-2 and 215 pounds, is hitting .370 with an Atlantic Coast Conference-leading 21 home runs.
He said he was overcome with emotion when he heard the news with his family at a T.G.I. Friday's across the street from campus in Coral Gables.
''A lot of cheering. I don't even know what happened. I was crying,'' said Alonso, who was drafted by the Twins in the 15th round out of Coral Gables High in 2005.
``I was very, very happy. The Reds are a great organization and they have great players. I can't wait to meet Adam Dunn and [Ken] Griffey [Jr].''
Alonso conceded he was waiting to see if the Marlins would take him No. 6 overall. When they didn't, he moved forward -- and was chosen with the next pick.
''If the Marlins didn't get me, it was game on after that with anybody,'' he said. 'As soon as the magic Marlins passed up on me, I said, `All right, let's see what happens with the next pick.' And there it was.''
Was it a disappointment the Marlins passed him?
''Uhhh. I don't know,'' he said. ``It was interesting, interesting. No comment. Now, obviously, I'm more of a fan for the Reds.''
Alonso was especially low key in UM's dugout after emoting earlier with his family. He said his priority was the UM postseason.
''This is a little more important right now,'' he said. ``I have to take care of these guys and see what happens after that. You play the game to win a championship and get to the major league level. It's amazing. It's a blessing.''