The Royals have traded for A's infielder/outfielder Ben Zobrist, who had previously been among the Pirates' reported targets. The key part of the Athletics' haul is lefty Sean Manaea, a highly regarded first-round pick from last year who's struggled with injuries. 25-year-old Aaron Brooks, a righty control pitcher who's had some success in Triple-A, is also headed west.
Manaea in particular is a lot to give up for a rental, although Zobrist has had two straight good months and has obvious utility for the Royals, who have Alex Gordon on the disabled list and who haven't gotten much out of second baseman Omar Infante. Pretty much every contending team could have used Zobrist somehow, so it's no surprise that the A's got a good prospect for him. Manaea probably currently rates somewhere near the back end of the top 100 prospects in baseball, so a roughly equivalent player in terms of value might be someone like Alen Hanson. The Pirates' need for someone like Zobrist was ameliorated somewhat with their addition of Aramis Ramirez, so it's not surprising they didn't want to pay the Athletics' price.