GEELONG has suffered a huge blow ahead of Friday night's semi-final against Sydney with key defender Tom Lonergan a late withdrawal with illness. 

Lonergan has been replaced by Rhys Stanley in the Cats' 22, while the Swans have named an unchanged line-up. 

Lonergan's absence means the Cats will have to rejig their backline and find a new opponent for Swans superstar Lance Franklin.

The veteran backman has enjoyed a good record on Franklin in their recent clashes, holding the two-time premiership player to 22 goals in 12 games.

Lachie Henderson or Harry Taylor now loom as Buddy's most likely opponents.

It's understood Lonergan is recovering from food poisoning, but he will face retirement on Friday night if the Cats lose, having played 208 games for the club.

Friday, September 15

Geelong v Sydney at the MCG, 7.50pm AEST 

LATE CHANGES
Geelong:
Tom Lonergan (illness) replaced in the selected side by Rhys Stanley
Sydney:
Nil

FINAL INTERCHANGE BENCHES
Geelong
: Darcy Lang, Sam Menegola, James Parsons, Zach Guthrie
Sydney: Harry Cunningham, Dean Towers, Nic Newman, George Hewett