Heat’s Dru Smith out for season with knee injury. Duncan Robinson day-to-day, but out vs. Knicks

Wednesday’s win over the Cavaliers in Cleveland proved to be a costly one for the Miami Heat.

Heat guard Dru Smith and forward Duncan Robinson sustained injuries in the victory and underwent MRIs in New York ahead of Friday night’s matchup against the Knicks at Madison Square Garden.

Smith will miss the rest of the season after an MRI revealed a third degree ACL sprain in his right knee. The injury will require surgery.

Robinson will miss Friday’s game against the Knicks and has been labeled by the team as day-do-day after an MRI confirmed he sprained his right thumb.

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Smith suffered the season-ending knee injury during the first half of the Heat’s 129-96 blowout win over the Cavaliers on Wednesday at Rocket Mortgage FieldHouse.

Shortly after entering the game for the first time with 9:06 left in the second quarter, Smith was injured when he attempted to close out on a Max Strus corner three-point attempt.

The court in Cleveland is elevated for better fan sight lines, featuring a ledge with a drop-off in front of each bench. Smith was injured when he inadvertently stepped over that ledge.

While attempting to close out on Strus’ corner three-point shot, Smith jumped in the air and landed with his right foot on the edge of the ledge in front of the Cavaliers’ bench. Smith’s right leg then awkwardly slipped off the edge and he immediately grabbed his right knee.

“It is a dangerous floor,” Heat coach Erik Spoelstra said after Wednesday’s win in Cleveland when discussing Smith’s injury. “I don’t know the history of injuries here. But we’ve had a couple scares in previous years when guys are closing out in that corner. Thankfully, nobody has been injured before. But it’s an accident waiting to happen. You close out and then all of a sudden you’re going off a cliff. It’s just so dangerous.”

Heat trainers then carried Smith to the locker room with 7:45 left in the second quarter, with Smith unable to put any weight on his right leg. Smith never re-entered the game.

“It’s really unfortunate for an effort play,” Spoelstra continued. “If the court was normal, I think there wouldn’t have been any kind of incident.”

Smith, 25, appeared in nine games this season after being promoted from a two-way contract to a standard contract just days before the start of the regular season. He totaled 39 points on 15-of-33 (45.5 percent) shooting from the field and 7-of-17 (41.2 percent) shooting from three-point range, 14 rebounds, 14 assists, nine steals and three blocks in 131 minutes this season.

While not in the rotation when the Heat’s roster was close to full health, Smith provided much-needed depth at point guard. Starting point guard Kyle Lowry is the only other true point guard on Miami’s 14-man standard roster.

Smith signed a two-year partially guaranteed contract with the Heat to join the standard roster before the start of the regular season last month. He’s had $425,000 of his $1.8 million salary for this season guaranteed, with his full $1.8 million salary becoming guaranteed on Jan. 10.

But because Smith suffered a season-ending injury, his full $1.8 million salary for this season counts toward the Heat’s salary cap and luxury tax/apron. He will also be paid his full $1.8 million salary for this season.

Smith’s $2.1 million salary for next season remains non-guaranteed.

The Heat now must decide whether it feels the need to add another guard to the roster to bolster its depth at the position with Smith out for the rest of the season. With 14 players on standard contracts, the Heat has one open spot on its 15-man standard roster that it could use to add a free agent guard or promote one of its three current two-way contract players (Jamal Cain, Cole Swider, R.J. Hampton) to a standard contract.

Among the point guards still available as free agents are former Heat guard Goran Dragic, as well as George Hill, Kendrick Nunn and John Wall.

The Heat could also bring back guard Jamaree Bouyea, who was cut by the Portland Trail Blazers from a two-way contract this week. Bouyea returned to the Heat’s G League affiliate, the Sioux Falls Skyforce, after being released by the Trail Blazers.

While Robinson’s injury is not as serious, his absence will be felt by the Heat for however long he’s out.

Robinson, who injured the right thumb on his shooting hand during Wednesday’s win over the Cavaliers, has been one of the Heat’s best players through the first month of the season. He’s averaging career-highs in points (14.5 per game) and assists (2.7) while shooting an efficient 47.8 percent from the field and 43 percent on 7.1 three-point attempts per game.

Among the 31 players around the league who entered Friday averaging seven or more three-point attempts per game this season, Robinson holds the third-best three-point percentage behind only Indiana’s Tyrese Haliburton (46.2 percent) and Golden State’s Stephen Curry (43.7 percent).

Robinson opened the season as part of the Heat’s bench rotation, but he started seven straight games in place of the injured Tyler Herro before missing Friday’s matchup against the Knicks.

Last season, Robinson missed six weeks after undergoing surgery on his right middle finger in January.

Along with missing Smith and Robinson, the Heat will be without Herro (right ankle sprain), Nikola Jovic (G League assignment), Orlando Robinson (G League assignment), R.J. Hampton (right knee sprain) for Friday’s game in New York.

The Heat closes its five-game trip on Saturday against the Brooklyn Nets at Barclays Center on the second night of a road back-to-back set.