Inverness have agreed to sign Simon King on Wednesday when his contract with Gillingham expires.
The 29-year-old defender should be eligible to join Terry Butcher's squad for Saturday's Scottish Premier League opener at St Mirren.
King cost Gillingham £200,000 when he signed from Barnet in 2007.
"Simon has agreed to sign on Wednesday and that completes our first team pool", said Butcher. "He's a useful acquisition with good experience."
King joined Oxford United in 2001 before moving to Barnet where he made 149 appearances.
He picked up a thigh strain while on trial with Caley Thistle but should be fit to join the squad for Saturday's trip to Paisley.