Boston Celtics guard Marcus Smart has been a crucial member of the Eastern Conference third-place team, with his tough defense more than helpful for Brad Stevens' squad.

Smart, 25, re-aggravated an oblique injury in Sunday's road win over the New York Knicks, taking a shot to the abdomen. Per NBC Sports Boston's Chris Forsberg, Stevens will be cautious in handling Smart, ruling out playing the Oklahoma State product if he's “super sore.”

“Sounds like it’s just like a contusion, so that’s good, but that doesn’t mean it’s not super sore. And if it’s super sore, he’s not going to play.”

Smart is averaging a career-best 11.9 points per game for Boston, appearing in 19 contests and starting in 14. Despite Smart leaving Boston's matchup with Atlantic Division rival Knicks over the weekend, the Celtics still pulled out the win. The next day Stevens downplayed the severity of Smart's injury.

“The only thing I heard is that it was — I don’t know if it was his oblique or right in that area — and they said it wasn’t as bad as in the past, so I don’t know what that means,” Stevens told reporters on Sunday, according to Logan Mullen of NESN. “I don’t know if that means — I’m sure we’ll get more information in the next couple hours.”

Smart has been a constant presence for the Celtics through the Isaiah Thomas years, Kyrie Irving's two-season stint in Beantown, and now All-Star point guard Kemba Walker running the show.

With Smart potentially sidelined, the Celtics would be surely hampered without their leader on defense.