Jetta collected eight disposals in the opening term, before limping off with a tight calf in the second quarter.
West Coast coach Adam Simpson said after the match that the extent of the injury was not yet known, but admitted that Jetta could miss the season opener.
“We don’t know, he’s never done one before,” Simpson said.
“But it looked like it was a grade one (calf) at a guess.
“We need him because at the moment we’re actually a bit light on with our midfielders. Last year we had a few backs out of action, but it’s probably adding up in our midfield at the moment.”
Defender Mitch Brown has also suffered another minor injury setback.
“Browny has got a sore finger,” Simpson said.
“We’re not quite sure how bad that is, so we’ve got to get a scan on that one.”