Celtics' Marcus Smart ejected for punching Spurs' Matt Bonner in groin

Some NBA ejections can ignite debates about the current state of refereeing and the role of toughness in this era of the league. Others are so obviously warranted that they require little explanation or argument. Boston Celtics rookie point guard Marcus Smart's first career ejection absolutely belongs in the latter camp.

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With just under 9:00 remaining in the fourth quarter of Friday's road game against the San Antonio Spurs, Smart wound up and struck veteran forward Matt Bonner in the area around his groin. Smart was quickly issued a flagrant-2 foul, triggering an automatic ejection. Take a look at the video, but be warned that it is not especially fun to watch:

People can disagree about Smart's level of intentionality, but the available evidence is not good. It sure looks like he closed his fist, wound up, and hit Bonner in a spot where people really shouldn't hit other people. For that matter, it's not immediately clear that Smart was reacting to anything Bonner had done, because he hadn't even entered the game until 22 seconds prior to the incident. Smart will surely be fined and likely receive a suspension for this play — the only question is how severe the punishment will be.

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Coincidentally or not, Smart's ejection preceded an 18-3 Celtics run that cut the Spurs lead to as low as seven minutes with several minutes remaining in regulation. Nevertheless, San Antonio finished strong to complete a 101-89 victory. Bonner, for his part, grabbed the rebound off Boston's final shot attempt.

This is not the first time that Smart has courted controversy. As an Oklahoma State sophomore last winter, Smart pushed a Texas Tech fan following an insult — audio recordings were inconclusive as to exactly what was said, but it may have involved a racial slur — and served a three-game suspension for the altercation. He apologized, returned to play well, and was selected sixth-overall by the Celtics in June's draft.

Smart has been inconsistent at the offensive end but has impressed overall and shown the potential to become an elite perimeter defender. Steve Bulpett of the Boston Herald relayed compliments on Smart's intensity in a story earlier Friday:

“I like the way he plays with that intensity,” said [veteran forward Gerald] Wallace, who understands that quality, having collected floor burns from every arena he’s visited. “We all knew he was a hard-nosed player and that he plays aggressive. We knew the hunger and the fight he had coming in, and he’s shown that out on the court.

The question now is if that same competitive zeal has imperiled both Smart and his team's playoff chances. At 30-38, the Celtics hold the final playoff spot in the East only via a tiebreaker over the Indiana Pacers. It would be a shame if the consequences of Smart's punch kept the Celtics out of the postseason, but a significant punishment may be a necessary response.

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Eric Freeman is a writer for Ball Don't Lie on Yahoo Sports. Have a tip? Email him at efreeman_ysports@yahoo.com or follow him on Twitter!