CLEVELAND — If David Fizdale is doing push-ups on the Garden sidelines during a game, you’ll know rookie shotblocking center Mitchell Robinson has improved his defensive posture.

Fizdale has a fun bet going with Robinson, the Knicks’ second-round project who has been plagued by foul trouble. Robinson’s problems, according to the coaching staff, stem from keeping his hands low and picking up unnecessary reach-in fouls.

So Fizdale has made it a contest.

“We got a little thing now where you guys will catch me sooner or later, but if he doesn’t do the foul where his hands are down, I got to do push-ups,’’ Fizdale said. “And if he does [foul with his hands down,] he has to do push-ups. So, you might see my body change here. For now it’s done just during practices.

“But I told him if he gets a couple of them in a row, I might make [us] do it in front of the whole arena.”

Fizdale had elevated the 7-foot-1 Robinson into the starting lineup after the season’s fifth game, but the 20-year-old wasn’t ready and got supplanted by Enes Kanter 12 games later. He’s back to coming off the bench and overall this season is averaging 4.9 points, 4.1 rebounds and 1.2 blocks in 17.6 minutes. This from a player who took a year off from organized basketball after high school to train for the draft.

“There’s no other way to substitute [not] playing for a year, especially at that age,’’ Fizdale said. “That’s a big development year for a young kid — to not be in five-on-five competition for all that time.



“This kid is mature and reliable. When he says he’s going to do something he does it. Comes to work every day. Never gives you attitude. You probably coach him the hardest, cause he’s the most raw out of all of them. He’s a joy to work with though.”

The deadline to convert undrafted rookie Allonzo Trier’s two-way G-League contract is now pushed back about a week from the original Dec. 15 because of his hamstring injury. Trier will travel with the club on the three-game trip to Cleveland, Charlotte and Indiana to rehab. None of those days will count on his 45-day clock.

That means the Knicks don’t have to reach agreement on a new regular contract and they have more time to decide who to cut to make room for Trier on the 15-man roster. The candidates are guard Ron Baker and center Luke Kornet. The Knicks could keep Baker to package in a larger deal for mathematical cap purposes as he’s worth $4.5 million. Also, trade talks should heat up Saturday because 2018 free agents become eligible to be moved.

Courtney Lee, back from his neck injury, has played three games and 26 minutes, but needs more playing time to get back into condition. Hence, Lee requested to play at least one G-League game with Westchester, starting with Wednesday’s contest in Lakeland, Fla. Lee, 33, will rejoin the Knicks in Charlotte.

“That was his decision,’’ Fizdale said. “I was like, ‘What a pro.’ The fact he came to us and said I’m hurting the guys, I have no legs and I have no rhythm. If it’s OK, can I go to the G-League and play some minutes.’’

The Knicks ultimately would like to showcase Lee to trade his long-term pact but Lee admitted Friday he’s in preseason form.

“It’ll probably take couple of weeks to get back get a rhythm and feel chemistry with the guys,’’ Lee said.