July 7, 2007 is the date of Sherk's fight against Hermes Franca.
What is the date of his first statement after the failed test?
One of those interviews states that he was stripped on Dec 7. So that interview happened after Dec 7. The EARLIEST it could have happened was 5 months after the Franca fight.
July 24, 07
"The following statement was released by Sean Sherk and his representatives, in regards to the recent suspension and fine handed down to the fighter by the California State Athletic Commission. Sherk has confirmed to the CSAC he intends on appealing their decision August 6th.
Sean Sherk Denies Doping Charges, Files Appeal With California State Athletic Commission
Brooklyn Center, MN (July 20, 2007)- Sean Sherk, the UFC Lightweight World Champion, has filed an appeal against the doping allegations of the California State Athletic Commission, and has retained Howard Jacobs of Los Angeles, California, to represent him in connection to those charges.
Mr. Sherk issued this statement:
"At the present time, I cannot explain the positive drug test in Sacramento, California . I know that I have never used any steroids or other banned substances, and I am investigating possible causes of the positive test with my attorney. I have never cheated, and all of my success has come from hard work and dedication to my sport.""
http://www.lockflow.com/forum/topic/sherk-issues-statement
August 1, 07.
http://mmajunkie.com/2007/08/dana-white-on-sean-sherk-i-believe-him
It isn't Sherk talking but it's the earliest article I believe is out there.