"They probably aren't in the top five (teams) if we're being honest."
I'm not so sure that isn't wrong. Notice he didn't say in the East. I think you could make reasonable arguments that at least 5 teams in the west are "better" than Boston, especially without Hayward. And that doesn't account for the Cavs, who I suspect many believe will be better than Boston when it counts.
I challenge you to name three teams better than the Celtics that aren't named GS or Houston (Houston, btw, has decidedly the weakest SOS at .490 among 10-win teams, but noone is talking about that).
I think you could make reasonable arguments that GS, Houston, San Antonio, Minnesota, and OKC are "better" teams than Boston or at least certainly a better playoff caliber team (and it wouldn't be totally laughable to put a team like Denver in that mix as well). Then you have Cleveland, Milwaukee, Toronto, and Washington from the East, who all could rather easily beat Boston (without Hayward) in the playoffs (notice I said could reasonably, not that they will).
Edit: to fix wrong team name
I disagree with OKC and Minn because like the Celtics, they have to prove something as well.
And can all the team in the East listed at least play like a top 5 team in the East first?
They do, but come playoff time, you need to win 4 games, which sets of players would you feel more comfortable with:
Butler, Towns, Wiggins, Teague, Gibson, Crawford, etc. or
Irving, Horford, Brown, Tatum, Smart, Morris, etc. or
Westbrook, George, Anthony, Adams, Roberson, Grant, etc.
It really isn't strange to think that OKC and Minnesota are better teams (or more likely to be a better playoff team) than Boston is without Hayward.
And BTW, Washington and Toronto are tied for 3rd in the East. Last time I checked 3rd was in the top 5. And Milwaukee is tied for 6th, a half game out of 5th.