In the wake of the reality that Broncos linebacker Von Miller worked with a urine sample collector in an effort to generate negative drug tests, the NFL was indeed concerned about other potential incidents.
Per a league source with direct knowledge of the relevant testing procedures and protocols, the NFL has investigated the situation and found “zero evidence” of any systemic or widespread issues with the sample-collection process.
Still, the league realizes that it’s impossible to completely ensure that corruption won’t occur. In any testing program, the integrity of the collectors ultimately must be trusted.
The league uses outside testing companies who hire collectors after checking their background and vetting them. Sometimes, a proverbial turd can land in the punch bowl. (It’s a fairly appropriate metaphor, in this context.)
The NFL and the testing companies utilize audits and other devices to check the work of the collectors. In this case, for example, we’re told that the chicanery with the aspiring chicken farmer’s sample was detected not by dumb luck but through the protections that previously have been put in place.
The league is committed to constantly improving the process. Short, however, of videotaping the entire process of collecting the sample (and all that that implies), transporting it to the lab, and then testing it, a chance of foul play exists.
It surely has happened before. It could happen again. With Miller, it happened -- and the NFL has taken all actions deemed appropriate in response to that fact.