BOSTON -- Kristaps Porzingis returned for the Boston Celtics on Monday night, checking into Game 5 of the NBA Finals with 6:49 left in the first quarter.

Celtics coach Joe Mazzulla had said Porzingis was "not quite ready" after he was made active for Game 4 and that he would be available in only specific situations in that game.

Ahead of Game 5, however, Mazzulla said Porzingis had progressed beyond that point and should be on the court. He added that Porzingis won't be on a minutes restriction.

Porzingis came off the bench, with Boston sticking with Al Horford at center to start the game.

Porzingis is attempting to play through the torn medial retinaculum allowing dislocation of the posterior tibialis tendon in his left leg that he suffered in Game 2. Like he did ahead of Game 4 in Dallas on Friday, Porzingis went through an extensive 25-minute pregame workout under the watchful eye of Boston's medical staff about three hours before tip-off of Game 5 at TD Garden.

After suffering the injury, Boston described Porzingis as "day-to-day." He sat out Game 3, then was listed as active for Game 4, though Mazzulla said Porzingis was "not quite ready" for game action and would be used only in very specific circumstances.

Boston didn't make Porzingis available to reporters Sunday, though in a very brief conversation with ESPN as he walked off the court, the center said he was feeling better.

The 7-foot-3 Latvian, who hadn't played past the first round of the playoffs before this season, missed more than five weeks because of a right calf strain suffered in Game 4 of Boston's first-round series against the Miami Heat. He returned for the NBA Finals, with Boston going plus-25 in the 44 minutes he played in the first two games and sitting at even across the 52 he did not, before he was injured during Game 2.

Boston acquired Porzingis a year ago in response to losing in the Eastern Conference finals to the Miami Heat, sending out fan favorite and former Defensive Player of the Year Marcus Smart in the deal. Porzingis went on to average 20.1 points and 7.2 rebounds for the Celtics during the regular season and is averaging 16 points, 5 rebounds and 2.5 blocks across his two appearances in the Finals.

The Celtics would claim a record-setting 18th NBA championship with a win Monday night.