Despite continued questions about its performance on offense, the Boston Celtics bench keeps contributing at an elite (non-starter) NBA level. It’s something they’ll need against the Knicks on Wednesday (Kyrie Irving out) and beyond (Marcus Smart hand).

In a high-profile win over the Cavaliers, Boston’s reserves looked to some observers to be a key to the game. And the bench didn’t let the observers down. Celtics reserves played about 100 of the team’s 240 minutes in that one. Yet they scored 48 of the team’s 102 points.

In a similar vein, Marcus Morris scored 19 as the Celtics rallied to beat the 76ers in London. (Morris has scored in double-digits in every game since — looking to extend his streak to 9 games against New York.)

And Marcus Smart Smart-played the Celtics to a win over the Rockets by becoming the first player in NBA history to draw two charges in the final ten seconds of a one-point game in NBA history.

Rozier, Theis step it up – on both ends

But if this assessment of the Celtics 5-12 unit is correct, then Scary Terry Rozier and Daniel Theis have been key catalysts.

It’s always dangerous to go by one statistical performance measure. But one straw in the wind may be the TPA (“Total Points Added”) player-effectiveness rankings. By the TPA measurement, both Theis and Rozier rank as the third and fourth most effective Celtics on the roster. (TPA adjusts player impact for minutes and number of possessions on the floor.)

The two, respectively, led the Celtics team in on-floor raw plus-minus in Celtics wins over the Clippers and Nuggets.

Theis has stepped up his offensive game with more playing time. For the month of January (11 games) he shot 50 percent from 3-point land heading into Wednesday’s game against the Knicks. For the season as a whole, he’s shooting a gaudy .606 (true-shooting percentage) from the floor. He’s averaging a double double (11.1 rebounds, 12.8 points) per 36 minutes played.

Both Rozier and Theis have made some down-the-stretch plays goo. “There’s a steal by Rozier” (so to speak) capped a Celtic comeback win over the Pacers. Theis’s fourth-quarter 3-pointer stopped a Warrior run and kept the Celtics in a game they nearly stole.

Mi-nute differences

With Marcus Smart expected to miss at least another week of action, Rozier should have a chance to shine even more. Note: In games in which he plays 27 minutes or more, Rozier is shooting 38 percent from 3-point range, and the Celtics are 9-2. (Yes, he plays more minutes in lopsided Celtic victories. Then again, four of those nine wins were decided by 10 points or less, and the Celtics are 4-1 in such games.)

Theis, for his part, has “earned a bigger role,” according to Brad Stevens. Indeed, Theis has played 18 minutes or more in 15 games this year. He has a negative plus-minus in one of them.

For a team that’s 25-1 when they win the rebound battle, that’s a hopeful sign too. Theis leads all Celtics in total rebounding percentage at 16.7. (Followed by Baynes, 15.5, and Horford, 13.0.) He also blocks shots at a rate (4.3%) more than 50 percent higher than any other Celtic (Horford, 2.8%).

“Rim protection and rebounding”? Danny Ainge, herzlichen grüssen bitte vor Daniel Theis.