Bayern Munich president Uli Hoeness has suggested that Bastian Schweinsteiger should "make Manchester United bleed" for his treatment.
Schweinsteiger left Bayern for United in 2015, but has not hit the same heights at Old Trafford that he did during a distinguished spell at the Allianz Arena.
Problems with injury and form saw him struggle to make an impact last season, before he was deemed surplus to requirements by Jose Mourinho at the start of this campaign.
"I would let them [United] bleed until the last day and then say goodbye," Hoeness told fans at a club meeting.
"I would play Golf every month, offer United my work and accompany [wife] Ana Ivanovic to Tennis matches.
"A club like that should be punished [for how they've treated him]."
Schweinsteiger has yet to feature for United in any competition this term and recent reports suggested he could leave United for a move to MLS in January, while Brazilian side Santos have also shown an interest.
However, Hoeness has hinted the 32-year-old midfielder could leave the game altogether in the not too distant future.
"From what I have heard, Basti is close to retiring from football," he added. "I do not think we would be doing him or ourselves a favour with a return to Bayern."
Schweinsteiger's contract with United is due to expire in 2018.