When Kristaps Porzingis concluded his first six-minute shift Wednesday night, he looked like he’d just run a marathon. His breathing was heavy. He was visibly fatigued. When he took his seat on the Celtics bench, he dropped his head and stared at the TD Garden parquet.

As the Knicks made yet another soul-crushing run in the fourth quarter Wednesday, all Kristaps Porzingis could do was watch.

BOSTON — The Celtics will be shorthanded for Game 2 against the Knicks, but as expected, it’s not too bad. Kristaps Porzingis was upgraded on the injury report from probable to available due to his illness. Sam Hauser, the lone player unavailable, went from doubtful to out with the right ankle sprain he suffered in Game 2.