An MRI on rookie Jayson Tatum's sore right ankle came back negative Thursday and he is listed as questionable for Friday's game against the Charlotte Hornets, according to the Boston Celtics.
Al Horford will miss his second straight game Friday while in concussion protocol.
Tatum left Wednesday's win over the visiting Los Angeles Lakers in the second quarter after complaining of ankle soreness. The team performed X-rays at the arena, which were negative. Tatum underwent more imaging during Thursday's day off and appears to be day-to-day.
Horford endured a blow to the head from Atlanta's Kent Bazemore in Monday's win over the Hawks and entered the league's concussion protocol Wednesday morning after reporting symptoms that included headaches to the team's medical staff.
Horford missed nine games last season because of a concussion but was at the arena for Wednesday's game, and team brass are hopeful this isn't as severe an occurrence.
The Celtics are already playing without Gordon Hayward, who suffered a season-ending ankle injury six minutes into Boston's opener against the Cleveland Cavaliers.
Boston has won 10 straight games after an 0-2 start.