I don't know if the Jets were his only option, but it was probably the best option for him contractually.
Free agency becomes a frenzy of owners throwing money at players. The Jets were at the short end of the stick with the top free agent QBS. They offered Teddy something that was more market competitive than many thought he would actually get. I think Teddy could have waited... I can't imagine he would have been hard pressed to find someone willing to give him an opportunity to compete...
But, who else would have given him a $1m guarantee and $6m total for 1 season? No one. Signing that NY deal is a no brainer. That's a great deal if the season ends up being a year long rehab season...
... and even if they cut him, he pockets a $1m and ends up signing elsewhere.
Proving he is healthy is important when it comes to financial commitment. If he stays healthy and shows even flashes of his former mobility, who is to say he won't command more money next free agency? When garbage QBs seem to get paid a ton in the name of stability, hype, or whatever, why wouldn't the market double down on a guy who is seemingly healthy?
Arguably, the Jets drafting a QB was the best thing that could have happened to Teddy contractually. B) The knee suddenly isn't the reason people expect him out of New York. The knee won't be an instantly believable justification for a decision to release him. If people expect it, teams will as well. If he keeps putting up wicked practice tape while the hype turns positive around his knee, he'll have a small little competitive market for his services if it happened before the coming season. If he makes it though the season, no one is going to knock him for not being able to hold the job from a No. 3 overall draft pick... He'll get P-A-I-D as a free agent next year.