I happen to like what I have seen from O-Tree. I also understand the need to bring him along slowly but I don't think any player that has the tools, gifts and mental capacity to play the game at a high level should be held back for the sake of development. If it were up to a few here, Ben Rothlesberger would have not won a Super Bowl his second season and wouldn't have played him his rookie year.
This is not an exact science and more times than not, most young players will benefit from having time to be brought along slowly. However, some players are more ready mentally technically and physically than others and should not be held back due to a general rule. The fact that O-Tree wasn't drafted has no bearing on if he is ready to play today. Just as some players regardless of how much you coach them or where they were drafted, just don't reach their potential or just don't learn to execute at a high enough level to play on Sundays.
Saying that, from what I have seen from O-Tree and from what we lack in the WR dept on the other side of the ball, I welcome any chance the coaches feel he can help us win games. If he already showed he can create separation, comes out of his moves on time, has shown he can catch the ball, showed he is very athletic and doesn't look like a rookie out there, then what's the problem? Point blank. If O-Tree can play.. Let him play.