What it looks like to me is that it may be the beginning of a leaf disease. Hard to tell from the pics. I would advise to monitor closely and do no water from overhead. Tomatoes should always be watered at the base of the plant. Have you had cool weather with rain lately? Those conditions can encourage diseases in tomatoes.
If the spots continue to grow or develop yellow or brown areas with black spots in the middle , it is most likely a disease, and will need to be treated. Copper based sprays work well on both bacterial and fungal tomato diseases.
