There is plenty of time between decision points.
1) Where will Josh go, and which coaches will he take with him? Or will Josh stay?
2) The team will see if they can come to terms before the final week of the season.
3) In the last 3 days, Brady can see actual "offers" and make his decision. The team CANNOT afford to wait and sign Brady later. In that case, there would be $13.5M of dead cap money PLUS anything on the new contract.
It is POSSIBLE that the patriots will come to terms with a WR or TE, and then give that information to Brady's agent. Of course, there is no guarantee that the team will follow through.
4) Finally, if the patriots cannot make a deal, Brady can spend a few days at most as a free agent. He would have already negotiated with several teams. The final decision will be done before April 1st.
Alternatively, Brady all sign with someone on the first day, and the team will be able to be more attractive to free agents.
We all have our guesses. teams will be able to present their current team, plus any new players secured in the first week (3 pre days plus 4 after the start) of pre-season. Some of these teams have $80M of cap space and will be able to show Brady a fine offense.
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Mid-March is a couple of months away. The most likely possible teams seem to be NE, TB, TEN, IND, LAC and CLE. Obviously, there are flaw with all the choices. My personal most likely are TB and TEN.