Yep, he would. He's buried behind a deep, much better, and well establiahed front court than Boston's. Mickey can't hold his jock... shouldn't use the two names in the same sentence. Rozier was a horrible pick. Expect a re- redo on Smart this year with BKN pick... Kris Dunn. That's all DA is comfortable with.
You can talk all you want about their units being better, etc., etc. but deeper they're not.
Portis wouldn't be getting playing time ahead of Sullinger-Olynyk-Johnson-Zeller add to that Lee and that's 5 players ahead of him depth wise, to say nothing of all the players Stevens uses when going small (Crowder/Jerebko) who'd be getting playing time ahead of Portis.
The reality in all of this, you can think what you want of Portis or how much of a stud he is, but he wouldn't be leap frogging any of these guys unless injuries occurred.
The Celtics bigs are much deeper than Chicago's and even then it took injuries for him to get playing time.
In fact, with all the NBA caliber bigs we have, there wouldn't be room for Portis to dress in the first place to get playing time.
BC, you know I have much respect for you.. didn't mean it as a personal attack. Just think Portis is going to be really good and was shocked at the selection. They're very high on him in CHI
I didn't took it as such, I argue heatedly (comes across more heatedly than I intend to, just the way I talk), no worries hehe

And I know that triboy's fanaticism with Mickey sours many on the player. But for all the hyperboles he presents, I do think Mickey should be a player in the NBA right now until shown otherwise. I think his defense alone, in a none-deep bench should assure him a place in a rotation just about anywhere from what I've seen so far from him. But it's all guesswork at this point regardless.
Anyways, the point in all of this is that whatever perceived talent gap there is between Portis or Mickey, we have too many NBA-ready players and veterans already in place to give playing time for a rookie even if he deserves it. That's simply the pecking order of things (and of course other posters would be quick to point out that the reason he's not getting playing time it's because the coach thinks he's not ready to play in the NBA, which I think is the wrong way of looking at things).
All this to say that esteem for a player's skill/talent is not the issue here.
I'll say this though, if Ainge thought enough of him to pick him high in the draft there may have been chances that Ainge doesn't go into free-agency and add two bigs in Johnson and Lee (though Lee is probably inconsequential as he was more valuable than Wallace, and even Johnson's value is in his contract, so maybe even then, so who knows), and maybe in that scenario the chances are increased of him earning a spot in the rotation.
But depth alone makes it too difficult as it is because he'd not be able to dress, and without dressing he doesn't even get a few minutes of playing time in blowouts and what not. Depth is too much of an issue with the Celtics, which really isn't with Chicago. They're more skillful, but the roadblock is thinner.
I mean, Zeller is not playing all that much for us as it is and he's shown that at the very least he can play in the NBA. He's young and it's in our best interest to play him as much as we can going in to free-agency, but still we haven't even as Lee to look as the odd man out.