The whale has a piece of metal stuck on its head. Whale experts aren't sure exactly what it is. They want to get close enough to see if it's real danger.
"The feeling is, it's causing swelling around the blowhole and it seems to make it difficult for the animal to open its mouth," said Pieter Folkens, NOAA whale rescuer.
That would mean the animal couldn't feed.
Volunteers are posted along the coast this weekend with binoculars.
The whale is thought to be moving north into Monterey Bay at up to four mph.
If you see it -- do not approach it. Take a picture, or video and call the Whale Response Hotline at 1-877-SOS-WHALE.