The Royals have been in the market for outfielders, considering the fact that they didn't have a viable right fielder. Rios fits that bill, as he has played 9,702.1 innings of right over his career, while being a pretty good fielder at the position.
Kansas City has been pretty quiet this offseason. They still need some starting pitching, as they will almost be guaranteed to lose James Shields to free agency. The American League champions have some work to do, but the acquisition of Rios fills the need out in right field.
Rios missed 22 games this season due to a thumb infection and contusion. Regardless, he has been very healthy over his career, failing to reach 500 plate appearances just twice over his big league career, in 2004 and 2006 with the Toronto Blue Jays.
This past season, the 33-year-old Rios slashed .280/.311/.398 with four homers and 54 runs batted in over 521 plate appearances. Rios' four homers were the second-lowest of his career. It appears as if his power is regressing. However, Rios was worth 0.2 fWAR, as he was below average both offensively and defensively. Rios posted a 92 wRC+ and a -3 defensive runs saved.
If he can regain his old form with Kansas City, Rios will definitely be a worthwhile addition. It's hard to get a primer outfielder at $11 million over one season, and Rios likely won't be a primer outfielder in 2015, but if he can just play to some of the same level he did in the past, the Royals may have a real steal on their hands. And as they hope to get back to the World Series, these are the gambles they have to make.
Rios went to high school in Puerto Rico and was drafted by the Toronto Blue Jays in the first round of the 1999 MLB Draft. Over his career, he has slashed .278/.323/.439 with 165 home runs and 762 runs batted in over 11 big league seasons with the Blue Jays, White Sox, and Rangers.