On the surface, it's a bit of an odd move, as Aviles is going through a difficult 2011. His slash line of .222/.261/.395 is brutal to look at, and the Royals only recently recalled him from AAA after his poor performance earned him an option to the minors.
Boston must like his versatility. Aviles can play third base or either of the middle positions, though his 2011 UZR is minus-0.8 according to Fangraphs.
Aviles' best year came in 2008 when he posted and .834 OPS in 102 games with Kansas City. He also managed an 11.1 UZR that season at shortstop.
Since then, however, his development has stalled. His career path makes the trade a little surprising. It's unclear what the team sees in Aviles that makes him preferable to Boston's existing options.
One of those was Navarro, who now heads to K.C. The Red Sox are content to give up on the 23-year-old utility man, who hasn't progressed as the organization had hoped. Through 16 big league games in 2011, he posted a .626 OPS.
His numbers at AAA Pawtucket were somewhat more respectable (.831 through 34 games), but the Sox obviously didn't see him contributing in the near future.
The right-handed Volz compiled a 3.33 ERA and a 1.05 WHIP in 51.1 innings with High A Salem this year. Despite those nice numbers, he's not on the organization's top 20 prospects.
Still, it seems like Boston just gave up a fair amount of potential for very little return. Other than providing depth at multiple spots, Aviles adds little to the team.
Were he an excellent defender, the swap might have made more sense, but this has the distinct feeling of a throwaway trade.
If the Sox are banking on a recurrence of vintage 2008 Aviles, they'd better be prepared for disappointment. And to send a pair of 23-year-olds packing seems rather rash given the team's needs.
The obvious but limited upside is his ability to man shortstop, a perennial sore spot in Boston.
At best this trade is a C, and that's only if Aviles improves on his first-half struggles.