Unfortunately there are more than a few to choose from.
Although very recent, AJ Jenkins is the worst excuse for a first round pick Ive ever witnessed. Every draft broadcaster was like "WTF" when the Niners picked him, but I trusted that Baalke saw something that no one else did. 2 years later and he's gone. The singular play of AJ that I remember about him was the cream puff Kaep tossed him with no defender within 15 yards of him. And he dropped it. AJ wasn't just a swing-and-miss draft pick. He was a swing-and-fall-on-your-ass-while-tearing-your-ACL draft pick.
Honorable mention to 2nd Rd. pick Glen Coffee, just for the way he left
[ Edited by theninermaniac on May 1, 2014 at 4:07 PM ]