When you think of the best players in baseball, FanGraphs wins above replacement last year was 5.7, and in the five years before that, he was worth 8.5, 3.7, 6.3, 5.9 and 5.4 wins above replacement.

His nERD of 0.86 means a lineup full of Zobrists would have generated 0.86 runs a game more than a league average player, 85th-best in the Majors. However, Zobrist garners much of his value from saving runs, with a defensive runs saved (DRS) of +11 last year.

Zobrist will mainly play second base for Oakland, a position they desperately needed to upgrade. but he has the capability of playing five positions (second, third, left, center and right field). Before the trade, the A's had Eric Sogard penciled in as their starting second baseman for 2015. Last year, Sogard hit .223/.298/.268 and was worth 0.3 fWAR. He'll become a valuable utility player in '15.

Oakland also shored up their shortstop position with the addition of Escobar, who was only worth 0.2 fWAR while hitting .258/.324/.340 in 529 PAs for Tampa last year, with a nERD of -0.47. Throughout his career, Escobar has been a decent fielder, but in his age-31 season in 2014, was rated as a below-average defensive player, with a staggering DRS of -24.

That -24 DRS is a huge departure from previous seasons, when he was a +48 in defensive runs saved as a shortstop. Oakland is undoubtedly hoping last year was a fluky season defensively for Escobar, and that he will return to being the four-win player he was for the Rays in 2009, 2011 and 2013.

For the Rays, this was all about dumping salary and selling high on a player who was in the last year of his contract. Zobrist will earn $7.5 million this season and is in line for a huge salary bump as a free agent after the 2015 season. They also free themselves of Escobar's contract, which is slated to pay him $5 million this year and $7 million in 2016. They also receive a decent catcher in Jaso, who hit .264/.337/.430 slash line last season, and is a career .259/.359/.399 backstop.

With this move, A's general manager Billy Beane showed his not ready to give up on 2015 just yet. After trading away Josh Donaldson, Jeff Samardzija, Derek Norris and Brandon Moss this off-season, Beane replenished his everyday lineup with two professionals that have a chance to make the A's much stronger up the middle. Zobrist gives Oakland tremendous flexibility, and Escobar should be an upgrade if he can get his defensive woes straightened out. They also join an infield with newcomers at third base, Brett Lawrie, and first base, Ike Davis and Billy Butler.

That's quite a facelift. And if things don't go well for Oakland in the first half, they can always turn around and trade Zobrist for a set of prospects at the trade deadline.

We'll see if it's enough to keep Oakland in contention in a very competitive American League West in 2015.