Shawn Marion has missed only one game in nine years against Dallas. The hobbled Miami Heat forward may not sit out Sunday, either, even though he may never play a more meaningless game against the Mavericks.

Dallas is expected to face Marion, a familiar foe, when it visits a Heat team on pace to finish with the worst record in franchise history.

The Mavericks (43-23) have won four straight against some of the East's worst teams, and now play the league-worst Heat (11-53).

Miami has been depleted by injuries in recent weeks, but Marion (back) is expected to return to the lineup after missing a 103-94 loss to Orlando on Friday night. Marion was acquired at the trade deadline from the Phoenix Suns, having been part of a rivalry with the Mavericks that included races for conference position and two playoff series.

Now, Marion will miss the postseason for the first time in four years. He aggravated his back earlier this week, but wants to return to the court even with the Heat in danger of finishing with a record worse than the 15-67 mark they posted as an expansion franchise in 1988-89.

"I don't want to sit here and have it keep nagging," Marion said. "If I can take a day off and get it right, it isn't going to kill me."

This would be the 42nd game - including 12 postseason contests - Marion has played against Dallas. He averaged 16.8 points and 13.1 rebounds for the Suns in the 2006 Western Conference finals versus the Mavericks, but Dallas won in six games before losing to Miami in the NBA finals.

Marion, one of the NBA's most dependable players health-wise, has missed only one game against the Mavericks in his nine-year career. A left ankle sprain kept him out of a 121-90 Suns win on Nov. 26.

If Marion is back in the lineup, he will be trying to help Miami snap a seven-game losing streak against Dallas, which hasn't lost in this series since a 119-118 overtime defeat on March 26, 2004.

Marion hasn't faced the Mavericks since they acquired Jason Kidd in a trade with New Jersey on Feb. 19. Kidd, who played with Marion in Phoenix, knows the Heat well from his years with the Nets.

Kidd is averaging nearly a triple-double in three games versus Miami this season with 10.7 points, 12.3 assists and 7.3 rebounds a contest. The veteran point guard flirted with a triple-double Friday night, finishing with nine points, 12 assists and seven rebounds in a 116-97 win over Indiana.

The Mavericks beat Charlotte, New York and New Jersey in their previous three games, with each win coming by at least 20 points.

Miami, meanwhile, has lost seven straight.

The Heat are expected to be without coach Pat Riley for the second straight game. At the request of team owner Micky Arison, Riley has been spending time scouting college talent in the coming weeks at conference tournaments and the NCAA tournament. Ron Rothstein will fill in for Riley.