Earlier today, one bit of news simultaneously hurt Boston’s chances of pulling back to .500 and built the stage for a meeting that could be monumental. Derrick Rose told ESPN’s John Buccigross he will play tonight against the Celtics. His presence makes Chicago considerably more formidable, as the presence of a defending MVP normally does, but it also allows us to gauge the Celtics against the team that has played better than any other in the Eastern Conference, at full strength.

The Celtics are also at full strength, thanks to the addition of Mickael Pietrus, whose debut fashioned considerable impact despite a stat line — five points, two steals, one rebound, zero assists, 1-4 on threes, 2-5 from the field — that suggested otherwise. Pietrus’ play inspired Boston. It allowed fans to look at a lineup that included Avery Bradley and Keyon Dooling — a backcourt capable of causing nightmares (or bricks, in Bradley’s case) to rain down on Faneuil Hall — and see potential for a crew that can apply pressure 94 feet from the basket, force turnovers and turn them into easy baskets.

Pietrus defended smaller players full court. He dealt with Lamar Odom in the post. He took a charge underneath the hoop after Brandon Bass got stuck fronting his man. He picked an opponent’s pocket and strode in for a rim-rattling dunk. But mostly, he helped because his style meshed with Boston’s second unit. The bench transformed in one night from a formless blob into a crew with an identity, a pesky, quick, hard-nosed defensive group that wants to bother opponents and force them out of their offensive game plan. That Pietrus can shoot is an extra, one the Celtics need, but his willingness to play defense in his opponents’ jock strap for 94 feet is why he could change the entire face of Boston’s second unit.

(Note: Pietrus also missed a miserable 27-foot three that came with the Celtics down four in the fourth quarter and charging. I saw it. But let’s not discuss that. STAY POSITIVE, PEOPLE!)

Boston could use a win. Leaving the TD Garden tonight at 4-6, on a three-game losing skid (all at home), without a single win this season against above-.500 teams, would not be a good look. But clawing to .500, against the Eastern Conference’s best team so far, would.

Rajon Rondo vs. Derrick Rose. Tom Thibodeau against his old mates. The Celtics attempting to push fans away from the ledge. The Bulls trying to keep the good times rolling.

This one could be fun. Or, it could be the latest painful chapter in a book that hasn’t started nearly the right way.

(Editor’s note: I’m covering a high school game tonight for my local newspaper, so the recap will be posted a little late.)