Chevy has known for many months that Trouba is going to be tough to sign. All the rumors over the past few months are likely true that Trouba has been available. Chevy has obviously not been offered the return he would like yet. His best return is likely trading Trouba now or before the season starts. If Trouba sits out after the season starts, his value is going to go down. If he sits out the year, it will further decrease his value.
Chevy has a choice and can get the best deal available now or risk a lesser return in a few months or after he sits out. Trading Trouba now is best for the Jets. Chevy can prove he is right and make him sit. Depends on what is more important, his ego, or the Jets.