BOSTON (CBS) — An already-thinned Celtics team is set to be without a starter for Game No. 3.

Marcus Smart, who started for the Celtics against Milwaukee after coming off the bench vs. Cleveland, will likely not play Friday night in Philadelphia due to ankle injuries suffered during that loss to the Bucks.

Smart is just 23 years old, but he’s the longest-tenured member of the Celtics after getting drafted sixth overall in 2014. In two games this year, he’s averaged 12 points, 8 rebounds, 3.5 assists and 2.5 steals per contest.

The Celtics are, of course, already without Gordon Hayward, who suffered a fractured ankle in the opening minutes against Cleveland. Smart took Hayward’s place in the starting lineup, but Brad Stevens will need to roll out his third lineup in as many nights when his team takes the floor on Friday.