I'm quite sure you have access to a computer that is equipped with google. Simply type "jarvis landry hamstring" into the search bar and hit enter. I'm not going to debate whether or not it's the only reason he ran slow at the combine, he's the only one who actually knows. I do know that he ran 2 tenths faster at his pro day (coincidence??) but the damage to his draft stock was already done. Todd McShay stated the only reason he didn't have a 1st round grade on him was because of his speed.
http://espn.go.com/blog/new-orleans-saints/tag/_/name/jarvis-landry
“Jarvis Landry, I'd have a first-round grade on him if he could run. His times are so poor. But he's a great slot receiver, tough-guy football player,” McShay said.
For the record, I could give a **** what McShay thinks but I can only assume that many other "experts" felt the same way, that his game tape doesn't line up with his measurables in shorts and a t-shirt and they're not about to put a 1st round grade on a wr that ran a 4.77 at the combine, bad hammy or not.