NBA Finals: Kristaps Porziņģis available 'if necessary' for Game 4 as Celtics look to sweep Mavericks

Kristaps Porziņģis is a go for Game 4 of the NBA Finals, with the Boston Celtics looking to sweep the Dallas Mavericks for their 18th NBA championship.

Celtics head coach Joe Mazzulla confirmed Porziņģis would be active after missing Game 3 with what the team called a posterior tibialis dislocation in his left leg, per ESPN's Tim Bontemps. Porziņģis was previously designated as questionable Thursday.

Mazzulla specified Porziņģis would "only be used in specific instances, if necessary."

Porziņģis originally sustained the injury in the Celtics' Game 2 win, when a box-out collision with Mavericks center Dereck Lively II left the Latvian big man visibly limping down the court. He moved gingerly for the rest of the game and did not appear in the game's final four minutes.

The injury is said to be separate from the calf injury that kept him out for the previous two rounds of the playoffs.

Porziņģis' absence loomed as a massive blow for the Celtics, as the former Maverick was among the most impactful players in Games 1 and 2 despite coming off the bench. The Celtics outscored the Mavericks by a combined 25 points in those games, while Porziņģis was a combined plus-25, meaning Dallas played Boston to a draw in the non-Porziņģis minutes.

Game 3 wound up being the most dramatic game of the series, as the Mavericks took full advantage of the Celtics' missing big man by hammering the paint early and often. The Celtics regrouped enough to take a 21-point lead in the fourth quarter, but the Mavericks mounted a furious comeback that fell just short of a win.

Backup big man Xavier Tillman Sr. was solid enough filling in for Porziņģis, but it was pretty clear the Celtics were missing something without their regular-season starter.

Game 4 is scheduled for Friday at 8:30 p.m. ET (ABC).