Considering injuries and positional depth

Everybody on this site is rightly worried about Michael Crabtree's Achilles tear. Again, you should be. While I don't think this injury is going to sink this team, the loss of Crabtree for at least the first half of the season is a major blow to this offense. And, I hate to say it, the injury has the potential of being season ending. That may not be completely true, of course. A lot of people are saying that he could come back soon. There is precedent. We have the technology!

But, in light of this devastating injury, I thought it might cheer us up to talk about other things. Let's change the subject, shall we? To other potential injuries!

The reason why the Crabtree injury is such a blow is because he played a position of, well, slight need for this team in the short team. I mean, the team is stacked in terms of long term potential. But, I don't think anybody is comfortable with the idea of Anquan Boldin as our number one receiver. He is a good player, don't get me wrong, but I think he is a better number two receiver at this point in his career.

But this begs a question for discussion: what other unit on the team could suffer a key injury least successfully and why? If you're concerned about any sort of player jinx, please feel free to discuss in generalities about position groups. We're talking about depth.

Let's not count stuff like the kicker position. We all saw last what happens when a bicker is injured, but teams don't exactly expect that to happen. What would happen to our d-line, for example, if we saw a major injury there? I mean, we did see it last year with Justin Smith. His loss was a considerable one for the defense - particularly in the pass rush phase of the game. Even after he came back, the defense wasn't the same with a less than 100% Justin. But, even if it weren't Justin who was hurt out of the starting d-linemen, that unit would still suffer.

What other units would see considerable drop-off with a key injury? Or, what unit would weather the storm? Last year saw a huge injury to the RB corps, but as I seem to remember, a certain young RB stepped up and the unit continued to thrive...