Isaiah Thomas left the Boston Celtics locker room after Wednesday's 121-114 loss to the Detroit Pistons without talking to the media. The usually chatty guard said Thursday that he was angry and didn't want to say anything he regretted, and then proceeded to call out the team for its poor defense, via the Boston Herald's Steve Bulpett:

"Yeah," Thomas said yesterday as the Celts gathered for an event at Boston Children's Hospital, acknowledging he wanted to avoid the media in that moment. "Now my thing is to just not comment on things and let myself cool down, because it's very frustrating the way we're losing games.

"Yeah, I was very upset. I still am. I mean, somehow, some way, we can't lose games like that, especially on our home floor. We've all got to do better."

...

"Guys are getting more opportunities on the offensive end, so maybe that means they're taking a step back defensively, which is not good," Thomas said. "It's hard to play both ends of the floor at a high level, and that's why only a few players in this league can do that. But we've just got to get that mindset back of being a defensive team and then letting the offense take care of itself.

"It's fool's gold the way we're playing offense so good."

Isaiah Thomas is fouled
Isaiah Thomas: not thrilled with the Celtics right now. USATSI

The story of the Celtics' 10-8 start has been pretty simple. After adding Al Horford in free agency and being anointed the East's next big thing, they have lost what made them so competitive before Horford arrived. Boston was one of the best defensive teams in the NBA last season; this year, its defensive rating is ranked 20th in the league. Part of that is because Horford and forward Jae Crowder have been injured for significant stretches, but that can't explain everything -- back on Nov. 7, Thomas sensed a problem and said, "We're not as good as we thought we were." It sounds like he is frustrated by the same thing now -- unlike last year's team, the Celtics aren't outworking their opponents.

If you're taking the long view, Boston is better than its record indicates. There aren't many teams in the conference that can match its depth or its collection of draft picks and stashed players. When it is fully healthy for more than a week at a time, smart money is on an improvement. The Celtics have serious deficiencies right now, though, and they're failing to live up to both internal and external expectations.