My yard has ruts in it because of the sprinkler system I had istalled pryor to having my sod laid. Is there a way to fix this problem? :-[

Rolling it might help. How recently was the sod laid? If it will still pull up, you could pull it up and fill the low spot underneath it. Otherwise, it would mean filling and seeding. Likely the new grass would show leaving lines all over the yard. Sounds like another good argument for doing things right in the first place. Any filled area needs to soaked well before final grade.