Chael Sonnen stepped into retirement earlier this month after testing positive for two prohibited substances and voluntarily admitting to a third following a random drug test administered on May 24 in Las Vegas. On Saturday, it came to light that Sonnen tested positive again in blood and urine samples given at another random drug test administered on June 5 in Portland, Ore. Both tests were administered at the behest of the Nevada Athletic Commission because Sonnen at the time had been scheduled to fight at UFC 175 on July 5 in Las Vegas. NAC chairman Francisco Aguilar confirmed the second drug test to MMAWeekly.com following an initial report by MMAFighting.com . It’s not that surprising that Sonnen would test positive again less than two weeks after the first failed test. It is surprising, though, that two of the four substances he tested positive for on the Portland-administered drug test were different than those the first test showed