Next year will be his 4th year, so they can (and would) use their 5th year option, so you don’t have to commit to him long term yet…however, they would need to make the decision on the 5th year option before the season starts next year, so there is a decision to be made.
Very tricky situation. If the team continues to play like this to close the year, you absolutely have a core to work with moving forward. The defense needs to increase the pass rush but the 2nd and 3rd layers look good and you can tag JJ in the offseason. With or without Fields, they are ready to compete for a playoff spot. Do you put those hopes on Fields again, while using your draft capital to shore things up, or use your No. 1 on what you think is your next franchise QB, hoping to get some capital back for Fields, and still having pick 8-10 to use on an OL or DE