Blues general manager Larry Pleau said he was aware of the grievance but did not know any particulars and wouldn't have discussed the situation if he had read the appeal.
"Naturally, we're not going to comment on that anyway," Pleau said. "Until he passes a physical, he's suspended."
Blues spokesman Chuck Menke said he was unaware of any rules regarding how a team can deal with a suspension.
"This is an individual situation that's being dealt with on a case-by-case basis," Menke said. "This is a team decision and suspension. There's no contractural or over-riding policy."
The 33-year-old Tkachuk is the second highest-paid player in the NHL at $7.6 million. He had 33 goals and 38 assists in 2003-04.