Livingston manager Gary Holt has been admitted to hospital after a weights session.
The ex Norwich City midfielder and coach, 46, will miss today's Scottish Premiership visit of St Mirren.
He suffered an injury while training with his squad on Friday and will be monitored over the next couple of days.
Livingston expect him to take training on Monday, with assistant Davie Martindale in charge in the interim.
"We ask people to respect Gary and his family's privacy," Livingston said.
Former Falkirk boss Holt replaced Kenny Miller at the West Lothian club 12 months ago. He made 182 appearances and scored three goals for Norwich from 2000-2005.
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