8 Team Keeper (Keep 12, max 2 goalies)
C: Stamkos, Tavares, Getzlaf, Shaw
L: Kovy, Neal, Patches, Ericksson, M Foligno
R: Wheeler, Simmonds, Voracek, Cole
D: Chara, Del Zotto, Boyle, Yandle, Campbell, Kulikov, Nikitin
G: Lundqvist, Quick, Smith, Hiller, Brodeur
positions: C(x3), L(x3), R(x3), D(x6), Utility(1), G(x3), Bench(x6) =25 players.
Cats include: G(1), A(1), +/- (.5), PIM (.25), SHG (2), SHA (1), GWG (2), Hits and blocks (.1), W(2), GA (-.2), SV (.05), SO (5)
Before I give my opinion, let's look at the numbers to highlight each player's value in such a format. Firstly, I'll use the last couple years to compare as recent production is important and it more accurately shows Callahan's value. Then I'll see the effect a strong offensive season from Getzlaf will have on his value.
Getzlaf: 104 fantasy points in 82 games = 1.26 fpts/game
Callahan: 123 fantasy points in 76 games = 1.62 fpts/game
Getzlaf: 124 fantasy points in 67 games = 1.85 fpts/game
Callahan: 89 fantasy points in 60 games = 1.48 fpts/game
And for comparison's sake, let's look at Getzlaf's career offensive season 08/09:
Getzlaf: 143 fantasy points in 81 games = 1.77 fpts/game
The reason why his career offensive season is less productive (on a per game basis) in this format than 2010/11 is due to more games played, a lower plus/minus and less hits/blocked shots. Though you could argue that in a points league (is it?)
that having him play more games will be more helpful, as it's cumulative production over the course of a season.
If you feel that Getzlaf can get back towards his production in 2010/11, then I feel it's a good move since he's already proven that he can reach that next level. Does Callahan have more offensive upside? I'm not sure. Though his peripheral strength does keep him in the general vicinity, and it's not as one-sided as potentially first thought when comparing the two.
The other side of the coin is the need for your squad. You have good RW depth even though you don't have an elite player there. And you'd be relying on Shaw as your third starting C which you needed an upgrade. So, in terms of team needs, I feel that Getzlaf will be a greater help.