If you're not getting a draft pick in return I would probably stick with your pick. Or I would say it would be fair without trading out Ryan Grant (although that would never fly). But to not get any pick in return doesn't make any sense. Waiting until after the NFL draft or closer to your own draft will help, as was said before.
To be fair though, I think Ryan Grant is going to be next year's bust and this will become more apparent the closer we get to the season. IMO, I would consider making that trade if the guy also threw in his (likely late) 1st round pick.