Andy Pettite had a tremendous second half last year even if it was against the weak NL:
After the All-Star break in 2006, Pettitte was among the best starters in the National League, throwing 93.1 innings, giving up 88 hits and nine homers, walking 27 against 86 strikeouts, and posting a 2.80 ERA.
Now let's look at Barry Zito's second half:
He threw 95 innings, giving up 106 hits and 15 homers, walking 42 against 59 strikeouts, and posting a 4.55 ERA.
If Andy comes back and throws with the same consistency he did in the second half of last season, he's going to be an excellent number three behind Wang and Mussina.