The Celtics may be without two key rotation players for Tuesday’s road showdown with the Philadelphia 76ers. Robert Williams (knee injury management) was ruled out by the team on Monday afternoon while Jaylen Brown (lower back pain) was called questionable for the Sixers matchup. Danilo Gallinari remains out as he recovers from a torn ACL.

Brown was also listed as questionable for Friday’s win over the Jazz but he played through the pain in the victory while struggling individually on the offensive end. The All-Star was an ugly 5-of-19 from the field over his 34 minutes, scoring just 12 points in the inefficient effort while laboring through some observable pain at points of the contest.

Williams will miss his second straight game due to knee injury management but his absence shouldn’t be much of a concern due to the fact that Boston is playing a back-to-back contest on Wednesday night back home against the Raptors. Williams was expected to miss one of those games (the same is the case with Al Horford) so the athletic big man is expected to be back to battle Jakob Poeltl on Wednesday night in Boston. Look for Horford to get the night off in that matchup.

he Celtics will clinch at least the second seed in the Conference with a win in any of their final four regular season games or with a 76ers loss. The Celtics own a tiebreaker over the 76ers in any head-to-head tie after winning the first three games of the season series.

Boston will also keep their hopes alive for the No. 1 seed in the East with a win as they trail the Milwaukee Bucks by two games in the standings. Milwaukee will have to lose at least two of their final four games in the regular season for the Celtics to have a chance at catching them. Boston has won five of their last six games overall.