San Francisco >> Warriors shooting guard De’Anthony Melton suffered a sprained left ACL, the Warriors announced Thursday, sidelining him for at least Golden State’s Friday NBA Cup matchup against the Memphis Grizzlies.

Melton will undergo further tests to determine the timetable for recovery. Warriors head coach Steve Kerr didn’t know exactly when he injured his knee during the Warriors’ win Tuesday over the Mavericks.

“He’s obviously a really important player for us, the guy who we envisioned and has done a good job as the starting two-guard,” Kerr said. “It’s a concern, for sure, but we’ll know more over the next few days.”

The Warriors signed Melton to a one-year, $12.8 million deal after he missed most of last season due to back issues. When healthy, the guard is a menacing two-way threat as a point-of-attack defender and confident shooter. But Friday will already be Melton’s sixth missed game.

The past two games, Melton has started alongside Steph Curry, Andrew Wiggins, Trayce Jackson-Davis and Draymond Green. It was the Warriors’ most successful starting five so far, and Kerr wanted to stick with it going forward.

Warriors shooting guard De’Anthony Melton suffered a sprained left ACL, the Warriors announced Thursday, sidelining him for at least Golden State’s Friday NBA Cup matchup against the Memphis Grizzlies.

Melton will undergo further tests to determine the timetable for recovery. Warriors head coach Steve Kerr didn’t know exactly when he injured his knee during the Warriors’ win Tuesday over the Mavericks.

“He’s obviously a really important player for us, the guy who we envisioned and has done a good job as the starting two-guard,” Kerr said. “It’s a concern, for sure, but we’ll know more over the next few days.”

The Warriors signed Melton to a one-year, $12.8 million deal after he missed most of last season due to back issues. When healthy, the guard is a menacing two-way threat as a point-of-attack defender and confident shooter. But Friday will already be Melton’s sixth missed game.

The past two games, Melton has started alongside Steph Curry, Andrew Wiggins, Trayce Jackson-Davis and Draymond Green. It was the Warriors’ most successful starting five so far, and Kerr wanted to stick with it going forward.Melton’s injury complicates that.

Melton is averaging 10.3 points, 3.3 rebounds, 2.8 assists and 1.2 steals per game. He most recently played stout defense on Mavericks guard Kyrie Irving.

With about three minutes left in the Mavericks game, Melton appeared to fall awkwardly and get up gingerly. But he finished the game and played 26 minutes total.

Melton’s earlier injury this year was a mild back sprain. He said it was nothing like what he dealt with last season, but the team treated it with caution. Melton worked over the summer to strengthen his body, particularly his abdominal muscles, to try to prevent back flare-ups.

“It’s not a similar one because at first I didn’t know what it was, as far as what was causing my pain and discomfort,” Melton told this news organization in late October. “Two, it kind of turned into a stress fracture. So I know I’m nowhere near that. And I have a way better core base, strength in the system than I did last year. And the pain I was feeling last year was nowhere near.”

This is a knee injury, though. As a pro, Melton has never suffered a serious knee injury.

Perhaps he still has not. ACL sprains vary significantly in recovery timetable based on the severity. According to online medical sources, a minor sprain (Grade 1) typically takes a few weeks to heal. A Grade 2 sprain would be a partial tear, knocking a patient out for months rather than weeks.

The Warriors and Melton will know more when the results of more tests come back.

“First of all, even in Philly (last year), he’s trying to get right this whole time,” Buddy Hield said. “He works so hard. Every day, he comes in two hours before, gets treatment, works his butt off…Just got to stay the course with him, keep his faith. When he comes back, come back better.”