This comes after Smith engaged in a scuffle with Celtics shooting guard Jason Terry in Game 3. After the two got physical, Smith threw an elbow at JET, and officials ejected Smith from the game after calling the foul a Flagrant 2.
Per John Schuhmann of NBA.com, that was enough for the league to decide that Smith deserved to be suspended.
John Schuhmann @johnschuhmann
J.R. Smith has been suspended for Sunday's Game 4 of Knicks-Celtics.2013-4-28 01:00:22
Smith, the 2013 Sixth Man of the Year, has averaged 16.3 points per game during New York's series with their rival Celtics.
The Knicks currently own a 3-0 series lead over the Celtics, which has some believing that Game 4 isn't necessarily a must-win. However, New York hasn't won a postseason series since 2000.
Any playoff game for the Knicks is a must-win. Unfortunately, this one will be without their second-leading scorer.
You be the judge of whether or not this ruling was fair or foul.
For what it's worth, Smith ran off the court without contesting the ejection ruling once the foul transpired. For that reason, it's likely that Smith expected to be thrown out for his actions and thus prepared for a harsh ruling.
No matter what Smith may have believed, this is a serious void for a Knicks team averaging 87.3 points in the series with the Celtics.
During Game 1, Smith scored 15 huge points while Carmelo Anthony disappeared for the second and third quarters. Smith also came up with five rebounds and two steals, thus displaying his drastically improved defensive presence.
In Game 2, Smith upped his total to 19 points and made two of his four three-point attempts.
Prior to being ejected in Game 3, Smith matched his Game 1 scoring output with 15 points in just 24 minutes. Smith produced four rebounds, three assists and two steals in that time as well.
All in all, Smith has been the Knicks' X-factor throughout the duration of the season. They'll be forced to play without him for Game 4 of their series with the Celtics.
Can they win?