Marcus Smart is not used to coming off the bench.

The 11-year veteran had spent the majority of his previous six seasons as a starter, and he held that role for the Memphis Grizzlies early in the current campaign before an illness sidelined him for four games.

But since returning as a reserve, Smart has emerged as a spark plug for Memphis. He'll be in the same role when the Grizzlies, winners of six straight, visit the Dallas Mavericks, who are riding a four-game win streak, on Tuesday in an NBA Cup game.

Smart's scoring and defense helped the Grizzlies recover from a slow start last Wednesday at home against Detroit. He had nine points and three assists off the bench in the second quarter to help Memphis outscore the Pistons 37-18 and carry an 18-point lead into halftime.

Smart finished with a game-high 25 points and made 7 of 11 from beyond the arc, adding five assists and three steals in an efficient 20 minutes.

"That's a vet, that's a pro," Grizzlies star guard Ja Morant said. "That's what he brings to this team. Obviously, it's a different situation than he's been in in his career, but for him to embrace that and still push guys like Jaylen (Wells), who's in the starting lineup, to be even better, and then he comes in and makes a difference for us in the game. We're very appreciative."

While it has been an adjustment for Smart, he has contributed significantly in his new role. He has averaged 14.5 points in his four games back since missing time with food poisoning. The Grizzlies have won all four of their games by at least 11 points since Smart returned.

"You just go out there and do what you do," Smart said.

Changing Smart's role has given the Grizzlies the ability to start Wells, a 6-foot-8 rookie who provides Memphis more defensive length on the wing than the 6-foot-3 Smart.

"We're winning a lot of different ways," Grizzlies coach Taylor Jenkins said. "We have different guys stepping up every different night. We're getting contributions up and down the lineup, but sometimes one guy just starts staying in a little bit more."

Smart had 16 points in Sunday's 136-121 victory over Indiana.

"I couldn't be more proud of how he's embracing this," Jenkins said. "When a guy like that can do that, then you can see how everyone else can embrace, 'Hey, as long as it's with the intent of winning, we'll accept any responsibility we got.' "

Dallas, which also will be playing in its final NBA Cup group stage game, welcomed back Luka Doncic on Sunday in a 137-131 win at Portland. Doncic scored 36 points and added 13 assists after missing the previous five games with a wrist sprain.

"I (was) just happy to be out there and playing with joy," Doncic said. "Everyone was playing with pace, playing with energy and having fun ... I was happy to be able to go."

The Mavericks were already flourishing without the reigning NBA scoring champ and have won eight of their past nine. Doncic paces Dallas with 28.6 points and eight assists over 15 games, while fellow guard Kyrie Irving is second on the team with 24.8 points per game across his 19 outings.

Quentin Grimes has scored a season-high in three straight games for the Mavericks and dropped 28 on 9-of-13 shooting in the win over Portland.

--Field Level Media

Quickchart Matchup

Memphis Off vs  Dallas Defense
121.7 Points For 111.4 Points Against 48.8 FG% 45.1 FG% 47.9 Reb 44.1 Reb

Dallas Off vs  Memphis Defense
117.9 Points For 112.9 Points Against 48.6 FG% 44.1 FG% 45.0 Reb 43.1 Reb