Plenty of optimism on Kyrie Irving, caution for Jaylen Brown, waiting on Marcus Smart and surgery for Daniel Theis

Al Horford (illness) misses second straight game with a bad bug while Jaylen Brown remains in concussion protocol.

Kyrie Irving and Al Horford are trying to keep spirits up while missing time. (Boston Celtics)

BOSTON — Brad Stevens could be very much forgiven for how he opened Wednesday’s pregame briefing with reporters before his depleted Celtics did battle with the Washington Wizards.

“I’ve got to get my head wrapped around it all,” Stevens lamented.

The Celtics coach of course knew it was coming. He spent the first five minutes of the session giving injury updates on six players, Al Horford, Jaylen Brown, Kyrie Irving, Jayson Tatum, Daniel Theis and Marcus Smart.

Of those six, only Tatum was available to Stevens for the game.

But there some encouraging news, and it involved arguably their most important piece for the upcoming playoff run.

Stevens indicated that imaging tests on Kyrie Irving’s sore left knee came back clean. He missed his second straight game but remains day-to-day while battling the tendinitis that has given him discomfort in recent outings.

“Everything looked great, which is good,” Stevens said. “Just got some soreness and some pain in that knee and, again, not something that you wouldn’t have guessed he’d have some of. But obviously creeping up twice in 10 days, we want to be very careful with that.”

Stevens said Irving’s availability is “unlikely for Friday” but will travel with the Celtics on their upcoming two-game road trip. Stevens said that while Irving could play in one of the two games (at Orlando) on Friday and (at New Orleans) on Sunday.

Al Horford is expected back Friday in Orlando from a nasty bug that “knocked him out” for the last several days, Stevens said. Stevens added that Daniel Theis will have surgery on the torn meniscus in his left knee on Thursday.

The news on Marcus Smart is the most uncertain.

“(Smart will) go talk to another doc about what his chances are of playing without further injury, and also if he needs surgery or not, and what the recovery time would be,” Stevens said. “After all that information is gathered, he’ll make a decision [next week], along with all of us, about the rest of the year.”

Earlier Wednesday, during his weekly appearance on Boston sports radio 98.5 The SportsHub, Stevens said there is the possibility Smart could miss the rest of the season but there were too many unknowns at this point.

“There could be a slight chance that he’s back sooner rather than later, but I’d say that it’s not going to be any time too soon,” Stevens told the “Zolak & Bertrand” show. “And there’s a chance that he would not be back.”

Smart injured the right thumb diving for a ball in the second half along the baseline, it was the same hand he injured in Los Angeles on Jan. 22.

Jayson Tatum simply had back spasms from sleeping badly while Jaylen Brown remains in NBA concussion protocol.