Roy Halladay: Is He, Or Any Pitcher, Worth It?

As the "Roy Halladay sweepstakes" drag on, the question about whether to deal four or five top prospects for one player keeps coming up. The Phillies in particular seem to be playing hokey-pokey with J.A. Happ. Is it a good idea to trade top notch prospects for a potential Hall of Famer? Well, I decided to look at history to see what it can tell us.Obviously, it is rare that a former Cy Young winner gets dealt, but it has happened often enough to give us a track record: (note that I did not include 'rent-a-player' deadline deals). 1989: The Twins trade Frank Viola to the New York Mets for Rick Aguilera, David West, Kevin Tapani, Tim Drummond and Jack Savage. Mets: Viola went 38-33 in 2 1/2 years with the Mets, winning 20 games in '90 but the Mets didn't make the playoffs in his time there.Twins: Aguilera collected 275 saves over eight seasons with the Twins, with 3 All-Star appearances Tapani was a solid ML pitcher, going 75-73 in six seasons with the TwinsThe others didn't amount t...