My own personal definition is that an ace is someone recognized across the league as more than just a team's best pitcher. If you have an ace pitcher, you expect to win when he starts and it is built on multiple years. Last year, even though Hughes had ace-like stats, I just knew that the Twins had a chance to win. This year, I hope to get to that level soon. One year should not an ace make, whether it is a rookie year or year that could mean "breakout" or "fluke". From the other side of the field, when you are facing an ace you think "Man, I hope we can get a fluke run and try to make it stand up today." People may have thought that about Hughes in the second half of this year, but probably not right now. Radke and Baker gave the Twins a good chance to win. That's a really good thing but with my definition, it doesn't make them true league-wide aces.