Josh Beckett isn't an ace, but he isn't getting paid like one either. The new market puts ace type pitchers at 22-25 mil a season (Lee, Hamels, Verlander, Sabathia, etc.) and Beckett is making a little less than 16.
Fact is I think Beckett is a pretty good #2/#3. He strikes people out, has a low walk rate, and doesn't give up HRs. I think that is enough reason for optimism going forward. If you look at his season, I don't think the ERA tells the whole story. He's had 3 implosions but if you look at his other 14 starts he is pitching at a low 3's ERA level. Given that he actually has a pretty good QS% which means he at least gives his team a solid chance to win even if that haven't really been doing that in his starts.
I'm not opposed to dealing him, but if we have to eat 15 mil and only get a middle tier prospect then that is a complete waste.