I definitely think that this would be a good move for you. While I think people were too high on Tulowitzki (at least in my league) he is still a top 5 shortstop and a huge upgrade over Cabrera. He was slumping before he got hurt, but I think he'll figure it out and I think bad luck on balls in play must also have been a factor. I watched one game where he had, in three ABs, three consecutive hard hit balls that were hit right at a fielder.
That being said, I am glad that I traded him when people were still high on him. I packaged him and Erik Bedard for Miguel Cabrera, immediately before Tulo got hurt.
"I have great faith in fools; self-confidence my friends call it." ~Edgar Allen Poe