I have no idea with Jack. But he is now in NorCal, and his old coach and old owner have opened up shop 90 miles down the road. Sounds to me like a reasonable possibility
As for the "other team" signing Jack. In this case the other team is Cleveland, and so no, they aren't going to sign him. Here's what you have to remember, in theory we would be able to offer him:
1) a starting job, at PG
2) within 90 miles of his current home
3) playing for his old coach/defensive coordinator from last year
4) to a contract with one of his old owners from last year.
No other team in the league can boast all those advantages.
Now others can boast other things, but Cleveland isn't one of them (Cleveland's tally: a backup spot behind a 38min a night PG, new coach, new owner, across country, in city derided as often as Sacto).
Anyway, its a thought. Jack's numbers last season are largely on the same plane as IT's, except Jack is known as a good full sized defender. He would cost you more than IT...but only for a year as IT is due for a big pay bump in a year. And if you believed you could get a shotblocker in the draft with that pick, one who could play rotation minutes, then that shotblocker is going to be MUCH cheaper than buying one on the open market, where they are at a premium. Again, assuming there was a guy sitting there you thought we could plug in, and assuming you were confident in pursuing Jack...but those are big assumptions of course.