So depending on the source, the Sox were somewhere between $11.5 and $14 million under the CBT cap before this deal, which would put them $3-5 million under it after this deal.
Unless they are willing to exceed the cap, this certainly seems to eliminate any other significant FA acquisitions, including JBJ. They might be able to sign a cheap LHH backup for 1B, but that would be it, unless there are trades to free up some cap space (Benintendi or Barnes), as noted above. In that sense this is a curious move.
Unless, of course, they are willing to exceed the cap this year - which would be odd given their approach thus far this offseason, and the current state of their roster. It would open the door for resigning JBJ, or signing Ozuna, but I don't see this happening.