That certainly could be as well.
In my mind, if the LAX player took the nails out of the trash can and gave them to the police, that immediately rendered them useless in this investigation.
Might as well not collect them.
Even if he picked them up off the floor in the first place, the police shouldn't assume anything and should collect them properly.
I can just hear the court testimony...
"Sure my DNA is on them. Hell, I picked them up off the floor and put them in the trash, and later I took them out of the trash and gave them to the Durham Police Department."
As one of the attorneys said, news would be if there was NO DNA on the nail!