Brad Stevens gives updates on Marcus Smart and Jayson Tatum

Jayson Tatum underwent and MRI on his shin contusion and it came back “completely clear,” according to Brad Stevens.Winslow Townson/Associated Press/FR170221 AP via AP

WASHINGTON — The Celtics arrived at their morning shootaround on Tuesday with a skeleton crew. All of the regular rotation players other than Jaylen Brown and Terry Rozier are back in Boston, either to rest or to receive treatment for injuries rather than play in this meaningless game against the Wizards.

The most important workout was scheduled for later in the day, when Jayson Tatum and Marcus Smart would take the court at the team’s training facility and gauge their progress as they recover from recent injuries.

“They are in kind of in the first step of testing themselves, I guess you would say,” coach Brad Stevens said.

Tatum, who left Sunday’s game against the Magic due to a preexisting shin contusion, underwent an MRI that came back “completely clear,” according to Stevens. Smart, who suffered a bruised oblique when he collided with Magic center Nikola Vucevic on Sunday, told Stevens that he felt better on Tuesday.

“I’ve heard anything from he could be good to go by practice later in the week to, if he’s got pain there, whatever the case might be, it could be a little bit longer,” Stevens said. “But they haven’t given me an exact timeline. I don’t think we’ll know that until he really gets on the court and moves around, but it doesn’t sound like it’s a long-term issue.”

Kyrie Irving, Al Horford, Gordon Hayward, Marcus Morris, and Aron Baynes stayed in Boston, too. The Celtics added some reinforcement for Tuesday’s game against Washington by signing guard Jonathan Gibson. Gibson, 31, played four games for the Celtics last season and spent this year in the Chinese Basketball Association, where he averaged 33.1 points per game.

Wizards at a glance

■  When, where: Tuesday, 7 p.m., at Capital One Arena, Washington, D.C.

■  TV, radio: NBCSB, TNT, WBZ-FM (98.5).

■  Scoring: Bradley Beal 25.7, John Wall 20.7, Jabari Parker 15.0.

■  Rebounding: Dwight Howard 9.2, Bobby Portis 8.7, Parker 7.2.

■  Assists: Wall 8.7, Beal 5.5, Tomas Satoransky 5.0.

■  Head to head: This is the third and final meeting. Boston is 2-0 against Washington.

■ Miscellany: Wall (Achilles’) is out . . . Parker (knee) is questionable . . . Washington ranks 29th in team defense, allowing 116.9 points per game . . . Wizards C Thomas Bryant is fifth in the NBA in field goal percentage at 61.2.