The FAN is reporting that the rumored Randy Johnson trade is a done deal. Johnson to the DBacks for Luis Vizcaino and three prospects (the Yanks are adding a lot of minor league arms this offseason).
Unless they're extremely confident they can sign Clemens, the apparent desperation to dump the Big Unit is a mistake. Even at the age of 42, Johnson made 33 starts last year with a K:BB ratio of 172:60. Sure, his ERA was 5.00, but
this post by Nate Silver indicates that was largely due to bad luck. Before the trade, PECOTA projected Johnson to be the Yankees' ace in 2007.

In return, the Yanks are receiving a pretty good reliever and some mediocre prospects. The three prospects were ranked as the 18th, 19th, and 20th best prospects in the DBacks system by John Sickels, all receiving a C+. No list I've seen ranks them in the top 10. Here's the relevant excerpt from Sickels:

18. Alberto Gonzalez, SS, C+ (good glove)
19. Steven Jackson, RHP, C+ (excellent season in Double-A following mechanical rebuild)
20. Ross Ohlendorf, RHP, C+ (sleeper who throws strikes)

The DBacks, on the other hand, with a 1-2 of Webb and Johnson have greatly improved their odds in the wide open NL West.