Ukrainian Serhiy Honchar has been sacked by his T-Mobile team for violating their code of conduct.
Honchar was expected to play a big part in this year's Tour de France
Honchar, 36, was suspended on 11 May following abnormal blood test results during the Tour of Romandy.
The decision was "based upon follow-up tests completed in early June and additional information gathered during his suspension," a team statement said.
"Mr Honchar is released immediately and is free to seek employment with another team or company."
Honchar, who won two time trials in last year's Tour de France, has not failed a doping test and T-Mobile did not elaborate on the nature of the tests or give further information.