What Could Cause Blood-like Semen After Masturbation In An Elderly Man Who Takes Daily Aspirin?

I am over 70 and have not had sex for a long time nor have I masturbated for a long time. But having just masturbated I noted that the ejaculated semen was all blood like. I do not feel any pain or discomfort. Sunday night I did have beets for a late diner. I have been taking two regular Aspirin daily in morning for weeks which deals with a sciatic left leg issue. I do have some Naproxen 500 mg but have instead found the Aspirin works as well or better. I am concerned about my blood like semen.