The news was first reported by the Detroit Free Press.
The Lions had until Monday to match the three-year deal for the 27-year-old restricted free agent, who had a breakout season in 2014 with six sacks. Now, it looks like the team was not as laissez-faire about losing Johnson as they seemed.
At the least, it opens the door for Johnson to return depending on a ruling from the arbitrator. If they had absolutely no interest in signing him back, it's unlikely they'd go through the trouble.
The Lions were willing to let many of their key pieces on a once-dominant defensive line go this offseason and put themselves in this position by not offering Johnson a competitive tender.
The front is already projected to look drastically different. Based on the outcome of Monday's appeal, they might be able to keep one familiar face.