What does Zack Greinke signing with Arizona mean for the NL West?

Does Zack Greinke's signing with the Arizona Diamondbacks mean that we've seen the biggest shocker move of the offseason? Does it mean that the Winter Meetings next week in Nashville are going to be without drama?

Hardly.

The Diamondbacks have been hinting all offseason that they were going to make a push for pitching and subsequently a push to challenge the Dodgers and Giants in the National League West.

And while the general consensus is that Greinke was choosing to sign with the Dodgers or Giants, he wound up signing with the Diamondbacks for six years and $206.5 million.

Apparently, the Diamondbacks aren't done. They are also negotiating with another free agent pitcher, Mike Leake. The Diamondbacks, under general manager Dave Stewart, are not only getting better, they are raiding the pitching staffs of their division rivals.

The Diamondbacks are moving upward. They had a 15-win improvement in 2015: They had 64 wins in 2014 and 79 wins last year.

They had the second-best run-producing offense in the NL, led by first baseman Paul Goldschmidt and under-rated outfielder A.J. Pollock.

It's not out of the question that the 2016 Diamondbacks could be next season's version of the Cubs and Mets, teams that made significant improvements in a year and wound up in the postseason.

In short, the Diamondbacks have the offense to contend. They need to shore up their pitching, and that's what they are doing.

And it doesn't hurt that the Dodgers and Giants need pitching.

The Dodgers, Giants and Diamondbacks are similar. Each has a Cy Young-type at the top of the rotation and questions in the other slots.

Last season, the Dodgers were 43-22 when Greinke and Kershaw pitched. They were 49-48 when anyone else started.

Now, it's Kershaw and who else for the Dodgers? They missed out on free agents pitchers David Price (Boston) and Jordan Zimmermann (Detroit).

And at the last trading deadline, they added Alex Wood and Mat Latos, not exactly moves from a Dodgers-like team that prints money.

The Giants aren't much better. They have Madison Bumgarner, but after that, the rotation has Jake Peavy, Matt Cain, Chris Heston and prospects.

The Giants aren't sure what they will get from Cain. Peavy is a six-inning pitcher at best. They could use one starter for sure and likely two.

The Giants and Dodgers aren't used to playing second fiddle to a team within their own division. But that's what happening.

Pitchers like Leake and Johnny Cueto have never looked so good. Cueto turned down a $120 million offer from Arizona. Leake is negotiating with the Diamondbacks.

This season there are plenty of pitchers, on all levels, on the market. That's good news for the Dodgers and Giants.

The bad news is that with Greinke, Arizona already has the pitcher each team wanted and needed.