The American hurdler, who was disqualified from the event at the Lausanne Diamond League earlier this week for a false start, said if conditions were agreeable bettering the world mark of 12.87 seconds was within his reach.
"I think the world record is obtainable," Merritt told a news conference said.
"I just need the right conditions and I need to stay in the blocks," he said in reference to Lausanne.
"I need to execute my race like I've been doing all season all hopefully it'll come."
The field features Olympic silver and bronze medalists, Jason Richardson of the U.S. and Jamaican Hansle Parchment.
Merritt has dominated the event this year, with the most sub-12.95 second performances recorded in a single season.
American sprinter Tyson Gay, fourth in the 100 meters at the Olympics, will race over 200 for the first time in two years.
The 30-year-old, who won silver in the 4x100 relay in London, decided to concentrate on the shorter sprint two years ago after suffering numerous injuries.
"I feel like my body is ready for the longer sprint again," Gay said. "It will be a nice test for me going up against guys like (Churandy) Martina, (Nickel) Ashmeade and (Wallace) Spearmon who are all in good form.
"Young Adam Gemili from the UK is an exciting talent too. I'm confident I can put forward a competitive time."
Britain's Mo Farah will run over two miles in his first race since his 5,000 and 10,000 double at the Olympics, and the birth of his twin daughters on Friday.
"It's not going to be as big of an atmosphere as during the Olympics obviously, but I'm going to hopefully put on a show on here tomorrow for people that didn't manage to catch me at the Olympics," Farah said.
Jamaica's Olympic champion Shelly-Ann Fraser-Pryce and silver medallist Carmelita Jeter of the U.S. go head to head again in the women's 100.
Fraser-Pryce won the Olympic title by 0.03 seconds, but Jeter turned the tables on her rival in Lausanne with her own narrow victory.
"I'm excited about where female sprinting is at the moment," Fraser-Pryce said.
"You can guarantee that lanes one to eight will be competitive."
(Reporting by Josh Reich; editing by Tony Jimenez and Alison Wildey)