"We're adamant that we've in effect had three weeks of mediation, and we believe arbitration is the only route," he said.
"We're meeting at 1000 tomorrow (0800 GMT on Wednesday) to write what will hopefully be our final letter, to say we're rejecting this.
"We're back to square one, we are boycotting again."
The players boycotted after Heath Streak's tenure as the national team's captain ended on April 2 when he questioned the composition of Zimbabwe's selection panel.
The rebels, most of whom are experienced players, wanted arbitration on the captaincy, the selectors and the alleged poor conduct of Zimbabwe Cricket Union officials.
Zimbabwe were forced to select an inexperienced squad for the one-day series against Sri Lanka, who triumphed 5-0.
The first test against Sri Lanka starts in Harare on Thursday and the Zimbabwe squad of 17 includes rebels Streak, Sean Ervine, Ray Prince and Trevor Gripper.
