Vernon Davis is, correction: WAS, dropping passes left and right this year. Week 2 he dropped one in the endzone. Week 3 he dropped a pass when he had the safety beat by 5 yards and likely would have been a score. And those are just the impact plays that could have changed games I am talking about, the guy was dropping a LOT of passes. Davis can get open but he can't catch the ball.
Eric Johnson on the other hand has hands made of velcro. He catches the ball real well. And he can run the 10-20 seam route through coverage and make the catch. A couple seasons ago, he racked up 80+ receptions running that type of route all day long.
I would add Eric Johson IMMEDIATELY to your roster now that he is the lone TE in the offense for at least a month. Vernon Davis is out 4 weeks minimum with the broken leg. I figure that EJ is instantly a top10 TE, and starts over guys like Randy McMichael, Chris Cooley, or whoever else you whiffed on when you drafted a TE. With the way Alex Smith is throwing the ball, I could see EJ right up there with the Todd Heap's of the world in the weekly box score. That's a big time waiver pickup on TE when there really isn't very much else out there to pickup. Hopefully other owners in your league will chalk EJ up to a one week wonder and kinda of ignore the Vernon Davis broken leg injury. Don't make that mistake and miss your chance at this rare waiver gem.
The only real drawback to Eric Johnson is his tendency to get season ending injuries. Right now he is healthy and he is going to produce some big games. Even if he does get injured at some point, you shouldn't expect him to maintain his scoring when Vernon Davis comes back. But EJ does give you time for an underperforming TE to right his ship and/or another TE to emerge to replace him later.
Personally, I think Eric Johnson is one of the better TEs in the league and the Niner's made a mistake looking for a stud TE in the first round this year. Shoulda drafted defense...and rolled with EJ all year long. Fact is, Eric Johnson may get banged up a lot, but he is an upper tier starting TE in the NFL when healthy. Right now he is healthy and he's been healthy the entire offseason as well. The guy is gonna come in a do a better job than Davis was doing in the first few weeks.