My guess is that over the weekend they did dip urine tests on the players and Frank submitted a positive test. When a positive occurs, it's possible that they send the urine sample to a commercial lab for GC/MS testing in the hopes that it is a false positive. False positives are extremely unlikely, even on cheap, easily available dip tests. This step may take a few days and may explain why Chewy said they knew several days ago (positive dip test) but Tyus and Eli didn't know until today (lab results confirming the positive dip test) that Frank wouldn't be playing.
Most recreational drugs (except marijuana) would be out of his system in 2 to 3 days. If the result was positive for marijuana, and you request it, the lab can also provide a THC level in the urine, which will help you determine if the subject is likely to be able to submit a negative test soon, or remain positive for the presence of THC for longer if he were a chronic user or used a very large amount. For an overweight, low activity, chronic user residual THC could remain in your system such that you could continue to test positive for up to 30 days. An elite Division I athlete with extremely low body fat and who smoked one time briefly should test negative for THC in a matter of days, assuming he doesn't keep smoking.
