I'd be willing to bet that everyone downplaying the "boom or bust" tag on CJ has never actually owned him before. Anyone who has ever suffered through having CJ on their roster knows this is a very serious problem. I've had him for several years and he is a lineup-setting nightmare.
Trust me, the 2 or 3 weeks each year that he blows up are definitely not worth the 10 weeks he puts up fewer points than the WR4 on your bench. Even if it wasn't for the bum shoulder I'd be down on Chad - the injury makes it a no-brainer to avoid this guy. Don't be impressed by his year-end totals or his reputation as a top-5 WR - take the time to look at his game logs over the past few seasons and ask yourself if you'd be honestly happy with that in your lineup every week.

Last year, Chad had only 4 games under 60 yds and he had 5 100 yd games along with a 200 yd game in there.
The year before that was his most inconsistent year of his career, and he still finished with 4 100 yd games. Other than in 2006, Chad has been fairly consistent from a game to game basis (and yes I have owned chad numerous times). I think people actual overexaggerate his lack of consistency.
:(
Here are CJ's games after week 3 last season:3 catches, 53 yards, 0 TD
8 catches, 83 yards, 0 TD
3 catches, 102 yards, 0 TD
5 catches, 51 yards, 0 TD
3 catches, 48 yards, 0 TD
4 catches, 73 yards, 0 TD
8 catches, 86 yards, 0 TD
12 catches, 103 yards, 3 TD
6 catches, 86 yards, 0 TD
2 catches, 60 yards, 0 TD
6 catches, 78 yards, 0 TD
4 catches, 44 yards, 0 TD
Then in week 17, when 99% of fantasy leagues are already over, he put up 4 catches for 131 yards and 2 TD's. THANKS CHAD!
For a guy who was (until this year) drafted as a top-5 WR, these numbers are terrible. There's no other way to look at it.
Now, I will agree that he may present some value this season if he falls far enough in drafts, but I just want everyone to understand that his year-end totals are completely misleading - even though his end of season numbers put him in the top 5 or 6 WR every year, there is no way he is a top fantasy WR. On a week-by-week basis he will kill your team.