Zach Mettenberger's trainer explains diluted drug test, back issue

Zach Mettenberger produced a diluted urine sample at the NFL scouting combine in February, leading to speculation that the former LSU quarterback had a drug issue. Not so says his trainer, who said that the diluted sample was the result of over-hydration.

Following an ACL tear during his final game at LSU, Mettenberger spent most of the winter leading up to his pro day in April at the TEST Parisi Football Academy in Martinsville, N.J. working with club owner Kevin Dunn. Dunn oversaw a rehab for Mettenberger that went six days a week and saw the player at the facility from dawn till dusk.

And while a diluted sample is considered a failed test by the NFL, Dunn explained what happened.

“His surgery left him with two-thirds of a hamstring tendon; one-third was used to replace his ACL. Due to this rigorous protocol where he arrived at 7:30 A.M. and trained until 5:30 P.M, his hamstring began cramping,” Dunn said. “We then elevated his water intake to between one to one-and-a-half gallons of water per day in accordance with guidelines from the ACMS, NSCA, ACE & NATA - all of which are considered gold standard resources for our industry. We also increased his potassium and sodium intake to combat the cramping, which was successful.”

The failed test has led to speculation that there is a drug issue with regards to Mettenberger, something Dunn says is not true.

“The NFL stated that Zach had a diluted sample which meant he was over-hydrated for the test. According to the NFL, this classifies Zach as failing the drug test,” Dunn said. “An assumption is made that a player is trying to hide a foreign substance by diluting the sample. A prudent medical team would require a re-test within 24 hours if a sample was diluted to determine if there were in fact any banned substances in their urine.”

The NFL did not respond to a request for information on their standard for determining what constitutes a diluted sample.

But the diluted sample isn't the only bit of bad news for Mettenberger this week.

According to a report from NFL Network's Ian Rapoport, “several NFL teams have medically flagged” Mettenberger with a back issue called spondylolysis. The issue is something he dealt with through his college career, and the training staff at LSU denied that it was anything debilitating. Rapoport said he won't need surgery.

The report, when coupled with his ACL tear from last season, could cause his draft stock to plummet if NFL teams decide his an injury liability. Dunn said neither is a problem.

“His knee was reported at 97 percent of what his unaffected leg was at his Pro Day on March 9. Since then he has continued his rehab at LSU with Jack Marucci, head athletic trainer and will have no issue with full participation at rookie mini camp,” Dunn said. “His back presented no symptoms at all during his one-on-one training with me. There were no limitations that were made for any back issues. In fact, there was no mention of any back issues from LSU for the past two years.”

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Kristian R. Dyer writes for Metro New York and is a contributor to Yahoo! Sports. Follow him on Twitter @KristianRDyer

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