Well, remember, there were two factors going into the season that led most to believe he'd be useless for fantasy:
1) He was in a L-R platoon in RF with Eric Hinske
2) He had never shown any consistent ability to hit before
Neither of those factors are the case anymore. He is hitting the ball consistently well, and Hinske is a virtual non-factor anymore, Rios is starting about 75-80% of the Jays' games now, regardless of who they are facing. There also seems to be a fundamental explanation (i.e. changes in his batting stance) that explains why he has gotten so much better this year.
It goes without saying he is worth a pickup at this point, and you can probably start him with confidence too. His playing time will probably not change significantly in the next little while.
You've got a diamond, You've got nine men
You've got a hat and a bat, And that's not all..