DALLAS -- Mavericks superstar guard Luka Doncic will miss Saturday's Game 1 against the Utah Jazz because of his strained left calf, and significant concern remains for his availability for Monday's Game 2, sources told ESPN.

Doncic, who is officially listed as doubtful, has not practiced since suffering the injury in the third quarter of the Mavs' regular-season finale on Sunday. He has been undergoing extensive treatment and progressed to jogging on a treadmill during Thursday's practice.

"He's in good spirits and looks like he's improving," Mavs coach Jason Kidd said.

Recovery timetables from calf strains vary based on factors that include the severity and location of the injury. The average time missed by NBA players who suffered calf strains this season was 16 days, according to information compiled by InStreetClothes.com.

The Mavs have declined to specify the grade of Doncic's strain or state an estimated timetable for his return.

Doncic, a two-time first-team All-NBA selection who averaged 28.4 points, 9.1 rebounds and 8.7 assists per game this season, has played despite injuries in his previous two playoff appearances.

In 2020, Doncic was listed as questionable for Game 4 against the LA Clippers because of a sprained ankle and was not cleared to play until after his pregame warmups. He had 43 points, 17 rebounds and 11 assists in the Mavs' victory over the Clippers, which he capped with a game-winning, step-back 3-pointer to beat the buzzer.

In the 2021 series against the Clippers, Doncic suffered a cervical strain in Game 3, significantly limiting the range of motion in his neck. He struggled in Dallas' Game 4 loss but bounced back with a 42-point, eight-rebound, 14-assist performance in the Mavs' Game 5 win.

There is concern that Doncic could aggravate the calf strain, potentially sidelining him for the remainder of the playoffs, if he returns before the injury is fully healed.

"If he's hurt and he can't play, we're not going to roll him out there to jeopardize or put him in a situation to make things worse," Kidd said earlier this week.