Randy Johnson also had several other stats, that were worth a glance.
WHIP: 1.24
K/9: 7.55
He's not as bad as his ERA indicated. Going to the NL, and out of the AL East, should help his numbers out. He probably could post a low 4.00 ERA in the AL next year, if he can lower his .366 BABIP with RISP. (which skyrocketed his numbers)
Probably not, but the gap is not as big as you make it seem. Drew and Lugo will boost the offense. Matsuzaka will boost the starting rotation. Losing Johnson, and Sheffield makes the Yankees a weaker team. Melky Cabrera won't come close to making Sheffield's numbers, nor will Jeff Karstens.
Depends how much the D-Backs are willing to eat. Then again, if the Yankees are in a position to make a trade, they'll do it. No matter, if Johnson is traded.
I agree, that this is a great trade for 2008 for the Yankees, but it will be hurting them in 2007. Karstens is not a major league starting pitcher. His BABIP was .246, which indicates that he is rather lucky. He allowed 40 hits in 42 innings, even with those lucky numbers. Can you imagine how many hits he's going to allow, when his luck evens out?
His K/9 rate is very low for an AL pitcher. (3.88) It would be different if he's getting a lot of ground balls, but he's not. (.48) He can't expect to live in Yankee Stadium giving up a lot of contact, and a lot of flyballs.