After Sunday's game, Kemba Walker seemed to suggest that Boston simply was not playing hard enough. Joe Camporeale-USA TODAY Sports

The Celtics dropped to 13-13 with a loss to the lowly Washington Wizards on Sunday, raising new questions about Boston and its issues.

The Celtics lost 104-91 to the Wizards, who entered Sunday with the Eastern Conference’s worst record. Even worse, Boston trailed by roughly 20 points for much of the second half, struggling to make shots and occasionally showing frustration and getting back late on defense.

After the game, Kemba Walker seemed to suggest that Boston simply was not playing hard enough.

“[We] just need to play harder,” Walker said, via Tim Bontemps of ESPN. “That’s it. We’re not playing hard. We’re not playing as hard as we know we can.

“When you play hard, great things happen. And right now, it just hasn’t been consistent, our play. So like I said, we’re going to continue to watch film and learn from our mistakes and get better.”

It’s not what you want to hear from one of your leaders at this stage of the season. The Celtics have lost seven of 10 games, including back-to-back defeats against the Pistons and Wizards, the two worst teams in the East. They’ve popped up in trade rumors as they try to address their lack of depth on the wing, but the problems seem to run more deeply than that right now.

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