You might want to take a sample (the whole plant roots and all if you can spare it, large sample if you can't spare the plant) to your local extension office for a diagnosis. If it's a disease, they should be able to tell you which one and what to do about it next year.

Most of the services they provide are free, sponsored through state land grant universities such as Virginia Tech. Plant samples can be diagnosed at their office if someone there is qualified or they will be sent to Tech for diagnosis in the labs there. The extension service is a wonderful resource for gardeners. I highly recommend it to anybody with questions about their plants or soil.

Also, you all may have seen the article in yesterday's Washington Post about how difficult tomatoes have been this year, particularly the beefsteaks. I think it was the heat, although Ts are tropical.

However ~ I find BB's usually slightly larger than a tennis ball, slightly smaller than a softball. Happy plants with plenty of regular water will make mostly the larger size. Very similar to Celebrity, although my C's have a tendency to be a bit smaller.