Woj states that Boston's plan would require them to sign Hayward and then make a deal for George, which could include a contract extension prior to the trade should the Pacers allow the Celtics to negotiate with him before dealing. The Celtics can certainly provide the Pacers with the best return for George and would likely be willing to part with more should an extension be in place so it's a no-brainer for them to wait for Boston rather than move him before free-agency for pennies on the dollar.
Although George's agent has told the Pacers he'd prefer to be dealt to the Lakers, with Los Angeles being his rumored destination when he becomes a free agent after next season for some time now, it was reported in an ESPN story from Zach Lowe back in March that Gordon Hayward was one of the players he would love to play with most. This would also explain the Celtics wait-and-see approach beyond salary cap concerns, as should they have Hayward in tow then George would be more likely to sign an extension before a trade to Boston.
Speaking of the salary cap, things will get very dicey after next season should this sequence of events go down given that the Celtics will have three players at max/near-max contracts on the books and the guy who finished 5th in MVP voting this season, Isaiah Thomas, looking to get paid some big bucks as well. I'm sure this is a major concern for the C's front office but if they can get George and Hayward to town this summer I believe they'll do it and then worry about that problem when it arises. Our own Justin Quinn broke down a handful of salary cap situations around the league that may come up in the years to come including that very issue.
According to Woj the Celtics have deals in place to rid themselves of contracts they will need to shed if need be:
Boston has maneuvering to do with its roster, including the shedding of salaries to create space to position itself for this scenario. Boston has contingencies in place to make deals and start a possible Hayward-George scenario toward fruition, league sources told The Vertical.
Saddle up for a wild weekend as free-agency starts July 1st, this coming Saturday.