A lot of things go into this. If you are fighting to make the playoffs, I'd say it's too risky. Shockey is injury prone and I wouldn't want him as my only TE. You're not very deep at WR either. Smith has been going down hill for weeks now and Ward isn't very consistent. If Calvin gets healthy in the next couple weeks, he'll put up huge numbers the rest of the way. Also, check out the remaining schedules of Ryan and Cutler. Ryan might have some better matchups down the stretch.