Yes have been there and done that!
Running obviously out and most likely you can plan on three months or so out. I was put in a walking boot which really helped with pain relief but meant I could still drive, work and swim/ride.
A good sports doctor who knows triathletes is important, some can be very conservative and not let you do anything else but mine was excellent and allowed my riding and swimming to carry on as usual.
Can you share the formal MRI report at all? That will govern some of your management and the expected time away from running…
Good luck.