Large patch is a leaf and stem disease that occurs during warm humid periods. It usually occurs in Zoysia lawns that are over-fertilized with high Nitrogen during periods with frequent evening thunderstorms and night time temperatures over 75 degrees (evening thunderstorms lead to guttation, which gives the pathogen all it needs to spread). If you maintain weekly mowing, avoid watering in the evening, and keep a good balance of nutrients you aren't very likely to see large patch. As far as pet damage, this isn't uncommon, however the damage would have been done during the growing season, and the discoloration would have been very noticeable. Pet damage is similar to a fertilizer spill in that the urine has a high concentration of urea (nitrogen), which draws water from the root and dehydrates the plant very quickly. I am glad to hear that there is a solution, I was not familiar with dog rocks, so I'll have to look up more information to provide to customers with dogs. As for Spring fertilization, most granular pre-emergents use Potash as the dispersing agent. Potash improves the cell turgor in plants, making them more drought tolerant and less susceptible to disease. Don't begin Nitrogen fertilization until the lawn is at least 50% green. Zoysia is a low Nitrogen turf, so during the summer, avoid high Nitrogen fertilizer, especially during hot humid periods. Also, use a slow release fertilizer to avoid a burst of new growth. Too much new growth at one time is often all a pathogen needs to get into the lawn. Here is a link that might be useful: Serenity Lawn Service

One more test you can do is drag your fingers though it like you are trying to comb it. See if you detect "runners" called stolons. If so, I'd be pretty confident that it is poa trivialis. It's unusual for it to be spread out in patches like you have, but that might occur if the lawn has been aerated or verticut/thatched. If it is triv, the only thing that has worked for me is to cut it out and patch with sod. Maybe others have a different diagnosis or better remedy.

I patched some bare spots last year with some seed I bought at Ace Hardware in a large bin. It came up a little lighter green than what I had but I thought it was because it was new. This year all the spots are coming up with light green and beige/white blades mixed in.(The grass looks like the picture in the post that is titled "light green grass-help") Could I have gotten poa trivialis seeds in with the other? If so I want to get rid of it ASAP.

That's normal. Newer grasses just don't have the root systems and aren't adults, and haven't attained their full adult coloration yet. Give them time. It could be next fall until color matches the rest of the grass, but late next spring should show an improvement. If you want to push things along, you could scatter a little Milorganite in that area if you want. The iron will help kick things along a little. But lighter coloration in younger grasses is not a sign of anything wrong.