Tyson Gay makes his comeback to the track on Thursday after serving a one-year doping ban in what promises to be a stern test against fellow Americans Justin Gatlin and Mike Rodgers.
World athletics' governing body, the IAAF, announced last week it would not appeal the reduced one-year sanction for doping served by Gay.
Gay was banned in June 2013 after testing positive for a banned anabolic steroid in two out-of-competition tests.
His ban, reduced from two years by the United States Anti-Doping Agency (USADA) due to Gay's cooperation, ended on June 23.
And the IAAF said it would not challenge the reduction, calling it appropriate under the circumstances and in accordance with IAAF Rules.
"Lausanne has always been one of my favourite meets, and I'm thrilled to have it be my opening meet of 2014," said Gay.
"I have run fast times here. I have been training for several months, and will be ready on July 3."
Ironically, Gay's main opposition will come from two sprinters who have also served doping bans.
Gatlin won Olympic 100m gold in Athens in 2004 and bronze in London eight years later, but also served a four-year ban from 2006-10, while newly crowned US champion Rodgers was out for nine months in 2011 after failing a drugs test.
In the absence of Jamaica's Usain Bolt, still recovering from a longstanding leg injury, Gatlin is the world's fastest man this season, having clocked 9.86sec in windy Ostrava.
Rodgers finished second on that night in 10.08sec, but went on to win last weekend's US track and field championships - not attended by Gay or Gatlin - in 10.09sec, his season's best being six-hundredths faster than that.
"Hopefully, Tyson and Gatlin will have seen what I did here," said the 29-year-old Rodgers.
A total of 17 Olympic and world champions will be part of the line-up for the 39th edition of the Diamond League event in Lausanne.
In the men's high jump, a host of competitors are eyeing Cuban Javier Sotomayor's 1993 record of 2.45m, including Ukraine's Bohdan Bondarenko (2.42m), Qatar's Mutaz Essa Barshim (2.42m), Russian Ivan Ukhov (2.41m) and Canada's Derek Drouin (2.40m).
French world pole vault record holder Renaud Lavillenie is aiming for a fourth Diamond League victory of the year, while New Zealander Valerie Adams will bid for a 51st consecutive win.
Back on the track, newly crowned Jamaican 100m champion Nickel Ashmeade will race the 200m against compatriot Yohan Blake and Frenchman Christophe Lemaitre.
Blake, the second fastest man over 200m (19.26sec in 2011), missed much of last season injured but said he had trained hard to get back in shape.
Another Jamaican legend, Veronica Campbell-Brown, will race the women's 100m.