You want to know what is hilarious. My league refused to veto the pending trade that had Morales in it. Then when a re vote was called not a single person voted to overturn the trade. I don't even know why i'm a league that would screw there members like this and not give a damn about it.
Assuming the trade was finalized before the injury, I wouldn't veto it. Halladay is in a pending trade in my league should that be vetoed because he just upped his value with the perfect game? What if the Morales trade wasn't pending and had been put through on Friday?
That being said, if I was the one trading Morales away I would offer to rescind the trade.