Seidenberg, who suffered a knee injury in December and had surgery to repair both his ACL and MCL, recently returned to skating on his own.
"We're not counting on Dennis to be back," Chiarelli said. "We're going to be very cautious with his injury. He has been skating, but that's all I can say on it. It really hasn't changed."
Also, defenseman Adam McQuaid has been sidelined since Jan. 19 with a quadriceps injury, and it is uncertain whether he will return for the playoffs. He was originally expected to be back in the lineup after the Olympic break, but he suffered a pair of setbacks.
"We want to be careful on it," Chiarelli said. "It's not a major injury; it's a soft-tissue injury. We've been doing OK with the D we have, so we're going to be cautious with him."
Chiarelli wouldn't elaborate on the condition of forward Daniel Paille, who needed help off the ice and never returned after being hit in the third period Saturday.
Bruins coach Claude Julien on Sunday said Paille was "doing great," but that was all he would offer on his condition.