Analysis: Kyrie Irving (sore knee) out vs. Bulls

The Celtics announced Monday morning that Kyrie Irving will sit out Monday's game against the Chicago Bulls due to a sore left knee.

Brad Stevens told reporters in Chicago that the knee bothered Irving throughout Saturday's loss against the Rockets.

“He was playing and felt it throughout the night,” Stevens said. The revelation helps explain his lackluster performance on both ends against Houston.

The All-Star point guard has missed just six games this year due to a variety of ailments (fractured face, bruised quad, sore shoulder). Stevens indicates that it may not just be a one-game absence either for Irving to rest the knee injury.

BSJ Analysis: Any mention of a knee injury with Irving has to be a little bit worrisome based on the Cleveland.com report from a couple months back that he was threatening to have knee surgery while he was with the Cavs to repair some lingering issues. From the report:

According to sources, Irving needs minor knee surgery as a follow to the procedure he underwent during the 2015 Finals to repair his broken kneecap. It's not pressing -- Irving is averaging 24.5 points and shooting a career-high .477 from the field -- but the procedure would ease some of the swelling and day-to-day pain he feels.

Irving denied that report back in January and the fact that he has not missed any time this year due to knee problems is encouraging. Still, Stevens' insistence that this could be a longer absence than just a game for the 25-year-old makes this situation one to watch closely.

In the interim, the Celtics will have a tougher challenge against a Bulls team on Monday night that blew them out by 23 in Chicago without Irving in the lineup during December. This is clearly a different Bulls squad (no Nikola Mirotic and Robin Lopez tonight) and Fred Hoiberg is putting a bigger priority on playing young guys to help them pile up losses to improve lottery odds. Still, there are a number of players in this lineup that gives Boston fits (especially Bobby Portis), so the C's will have to maintain their focus tonight to avoid a letdown, particularly on the defensive end.

Stevens has given no indication yet on what direction he will go with for his starting five to replace Irving. Terry Rozier did well as starting point guard (three straight wins with Irving sidelined) last month, but Marcus Smart was not an option during that stretch. Stevens will have to weigh going with the more offensively-minded Rozier or sticking a defensive stopper in Smart to hold down the fort. The guess here is that he goes with Smart to keep the bench unit largely intact and since Smart's distributing mindset should help more with starters. Either way, Shane Larkin will likely slot in for a few backup point guard minutes with Smart or Rozier getting a promotion.

The Celtics are 4-2 this year with Irving out of the lineup.