Tony Modra's wife has thanked the two first responders who rushed to the AFL great's aid after a truck accident.

Modra is in a critical condition in an Adelaide hospital with head injuries after an accident on his cattle property on Thursday afternoon.

The former Adelaide and Fremantle star was injured when a tree branch was believed to have broken through the windshield of a truck he was driving.

Modra's wife Erica has expressed her gratitude to the two responders who were first at the scene of the accident at Back Valley, about 90km south of Adelaide.

Former Crows captain Mark Ricciuto, who remains one of the injured footballer's best friends, relayed text messages from Erica Modra on his Triple M breakfast show on Friday morning.

"She just wants to say a very big thank you to the first responders, called Sarah and Anthony, who saved his life and helped talk through to Erica while things were going down," Ricciuto said.

"She wants to thank the MFS and the emergency personnel at the Victor Harbor Hospital who stabilised him and got him sorted until the intensive care team took control and looked after him.

"She said he's going all right. It's pretty amazing that he's got through it."

Modra has lived on a beef and cattle farm at Waitpinga, south of Adelaide, since 2003.

The 57-year-old rose to AFL fame with Adelaide, becoming renowned as one of the game's greatest drawcards for his spectacular high marking and prolific goal-kicking when playing for the Crows between 1992 and 1998.

He then spent three seasons with Fremantle, playing alongside current Dockers coach Justin Longmuir.

"He's obviously a big part of the Freo family and all I can say is I wish him and his family well," Longmuir said after Fremantle's win against Geelong on Thursday night.

"Hopefully, he can pull through. I'm thinking of him. We're all thinking of him and his family."

SA Premier Peter Malinauskas and the state's opposition leader Ashton Hurn are among well-wishers for Modra - both describing him as an "icon" of the state.