Watermelon Ale

I recently brewed a watermelon ale extract kit from williams brewing. Just me being nieve, I didnt’t realize that you can brew any beer and add watermelon extract @ bottling. I’ve been doing some reading and am toying with the idea of cutting up some watermelon, freezing, and then adding @ secondary. Currently I have watermelon ale and raspberry wheat in my only bucket fermentors. I do have my 5 gal carboy free that I use for secondary. Question is, am I flirting with disaster adding fruit to a 5 gal secondary? I would add it to the primary, but I want to get rolling with NB BB Porter this Sunday, in which case I’ll need the extra head space for initial fermentation. This is kind of a “what would you do” thread. Thoughts?

Add it to the secondary.

+1 Definitely secondary.