Michael Rogers, a former Team Sky rider and three-time world time trial champion, has failed a drugs test.
The 33-year-old Australian tested positive for clenbuterol at the Japan Cup in October.
The International Cycling Union (UCI) says Rogers is provisionally suspended while his national federation investigates the case.
Team Sky's Jonathan Tiernan-Locke is also being investigated
after an anti-doping violation.
Rogers' team released a statement which stated that the Australian feared the positive result was due to a contaminated food source.
The Tinkoff-Saxo statement read: "Michael Rogers immediately informed Saxo-Tinkoff's management about the notification from the UCI.
"The Australian explained to the team management that he never ingested the substance knowingly nor deliberately and fears that the adverse analytical finding origins from a contaminated food source.
"Michael Rogers participated in Tour of Beijing the week before the Japan Cup and travelled directly from China to Japan."
Clenbuterol, which helps build muscle and burn fat, is the substance
two-time Tour de France winner Alberto Contador tested positive for at the 2010 Tour.
Rogers joined Contador at Team Saxo-Tinkoff last season from Team Sky, where he rode in support of
Britain's 2012 Tour winner Bradley Wiggins.
Rogers left Sky after being named in evidence in
the Lance Armstrong case
as working with the American's favoured doctor Michele Ferrari.
Rogers was upgraded to bronze in the time trial at the 2004 Olympics when Tyler Hamilton was disqualified for failing a drugs test.