Matthews has been diagnosed with a stress fracture in his right leg and will likely miss the remainder of the season, Shams Charania of Yahoo!
Matthews sustained the injury in Saturday's win over the Memphis Grizzlies and underwent further testing on Monday.
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An MRI on Tuesday revealed the stress fracture.
The Mavericks (21-46) didn't immediately provide a timetable for his return but it appears season-ending with only 15 games remaining and the team already eliminated from playoff consideration.
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Assistant manager Carlos Compagnucci and assistant first-team coach Xavier Tamarit have also parted company with the south coast club.
Matthews has averaged 12.7 points, 3.1 rebounds, 2.7 assists and 33.8 minutes in 63 games for the Mavericks this season, providing steady wing play and a veteran presence.
Matthews has struggled shooting the ball throughout the season, making barely 40 percent of his attempts from the field and 38 percent from deep.
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FOX19 NOW crews went to Partin's home on Monday to get her side of the story but were not able to reach her. Hannah's family said that bruises would pop up from time to time, but there was always an explanation.