Bath co-captains Crockett and Lipman and wing Higgins all protested their innocence and denied taking any banned substances.
All three were officially cleared of allegations of drug-taking but were subsequently banned for failing to put themselves forward for testing.
Crockett, who came up through the ranks at the West Country club, and Lipman, who currently has 10 England caps to his name, today lodged appeals against both the verdict reached by an RFU disciplinary panel and the sanctions imposed upon them.
Higgins, meanwhile, has instead decided to bring his playing career to what could be a permanent halt at the age of just 28.
The former Bristol player has stated that his desire was always to clear his name of the allegations of drug taking and that, having done so, the disciplinary process has left him disillusioned with the sport.
"Despite the fact that on the first day of the four day hearing myself, Michael and Alex were all completely exonerated of any drug taking , the RFU Disciplinary Panel on the August 3 went on to find us guilty of failing and/or refusing to submit to internal drugs tests without reasonable cause on two occasions. I was subsequently suspended from playing rugby until the February 28, 2010.," said Higgins in a statement issued via his solicitor Richard Mallett.
"I am deeply frustrated and totally devastated by that decision. A decision that has caused me to become profoundly disillusioned with the whole process and has led me to consider whether or not I wish to continue to be involved with the game of rugby at any level.
"As a result I have decided to 'take some time out' and take advantage of other options outside of professional rugby that are available to me. My main focus was always to clear my name in relation to any drug taking; this has now been done and I will not be taking the matter any further.
"I would like to take this opportunity to reiterate that I am immensely proud to have represented Bath Rugby club and will always be grateful for all the support that I have enjoyed from the players and fans.
"I wish the players and the fans every success."