Oates told reporters in St. Louis on Tuesday that Halak "wasn't 100 per cent comfortable" starting against the Blues, who sent him to the Buffalo Sabres in the Feb. 28 trade that got them Ryan Miller. Halak was then traded before the deadline to the Capitals.
"Jaro never at any time said he didn't want to start against St. Louis," agent Allan Walsh said in a statement sent to The Canadian Press. "A private conversation between a player and coach should stay private and not be discussed with the media.
"I am bewildered that a coach would break that trust especially when those comments the coach publicly attributed to Jaro are not accurate. It's the coach who makes the decision on who plays in the games, not the players."
Halak told reporters from the Washington Post and NHL.com after the Capitals' morning skate at Scottrade Center that the incident is still too "fresh."
Braden Holtby started for the Capitals and beat the Blues 4-1 to keep Washington's very faint playoff hopes alive.
A team spokesman declined comment when sent Walsh's statement.
Halak, 28, is set to be an unrestricted free agent this summer. The Slovak goaltender is 28-13-7 with a 2.29 goals-against average and .919 save percentage between the Blues and Capitals.
Before the past six weeks, Halak had only been traded once in his NHL career, when the Montreal Canadiens sent him to St. Louis for forward Lars Eller.