My dog does that when the grass is too high, too wet, or has snow on top of it. Any changes in the grass area?

Annz,
I had wondered if maybe the wet grass from the sprinkler system bothered him, but all of the grass conditions have been there his entire 7 years and nothing seemed to bother him until just recently.

Could be something spooked him. Shelties are easily spooked, our female Sheltie goes on the driveway all the time. If our male tries to play with her while she's getting ready to go, she reverts to the cement. Grass conditions can also bother them as annz noted.

I just thought of another reason my dog won't use his regular spot......if the coyote has paid a visit! I can tell by the way my dog cautiously approaches the area that the male coyote has been here and used/marked the area.
Do you have coyotes in your area?

Annz,
Yes we do have coyotes around. I can hear them now and then, but I haven't seen one in a number of years. I might add, however, that there are almost no cats where I live.
Jomuir, I noticed today that I have a reverse situation from you. My female was picking on the male. Maybe I ought to revert to letting them out one at a time and see if anything changes.

Like Annz, one of my dogs won't go in the grass if it's wet or too high, but in reality she would be quite happy to go on the doormat if I let her! -Wouldn't have to walk so far...

I think, off hand, your dog was spooked/scared by something in the grass and has chosen to avoid it but it could also be the other dog overpowering him. My male dog is Very submissive to our female dog, who is smaller, btw.

My female dog will lie in our male dog's bed, eat his food, take his bone, etc. if I weren't there to prevent it from happening (and I am always there) And he, my sweet, sweet boy, will let it happen.

Thank you Bumblebeez. I guess I'll have to learn to live with it and hope it doesn't last forever. I have watched him poop on the grass several times since all this started so he seems to be doing both--grass and driveway. It could be one of those "wouldn't have to walk so far" situations. He does have those leanings. He is also larger than our female, but basically submissive to her even though he was living here first. It's not quite as bed as between your two babies, but still noticeable. He has a much more docile nature. Oddly though, she is the shy scaredy cat with strangers while he is very outgoing.

If you figure it out, could you tell me what prompted it so I can get my dog to do that? I'd prefer rinsing off asphalt than deal with dead grass. My dog won't even "evacuate" on a walk. He insists on killing the lawn!

Susan Biesecker i feel your pain! i have 2 dane girls and live on 20 acres. one will do her business as far away as she can get, the other walks to the back yard and that's as far as she goes.