To concur with the others, I wouldn't say cracking the top 50 OF would amount to a huge breakout season, but I'll play along.
Personally, I don't expect much from Rios. Performance-wise, he's had only one notable season in his pro career, that being his age 22 season at AA New Haven (where he hit .352/.402/.521). That's certainly a great year and, as a center fielder, his rise as a prospect immediately after that season was warranted; but when you look at his other seasons, it definitely stands out in isolation:
20 2001 A Charleston .263/.296/.354 in 480 AB
21 2002 A Dunedin .305/.344/.408 in 456 AB
22 2003 AA New Haven .352/.402/.521 in 514 AB
23 2004 AAA Syracuse .259/.292/.373 in 185
23 2004 Maj Toronto .286/.338/.383 in 426 AB
24 2005 Maj Toronto .262/.306/.397 in 481 AB
He was rushed through AAA after performing rather miserably there, and he arguably regressed in 2005, putting up 28 BB/101 SO to go along with the numbers above. You can say he's still young, but it's probably foolhardy to predict big things in 2006 when all you have to look back on is that one great season in AA three years ago.