By my best estimate, it was 2001 when I first brought a 32 page baseball picture book concept to my writers' group (lead by local authors Jessie Haas and Michael J Daley) for a critique. Based on feedback from the group, I expanded it into a 48 page "reader" (an early chapter book), and titled it The Fuzzies' Big Inning. I started submitting for publication. As a published author and illustrator (the picture book Dinosaur Train) I am generally able to get my proposals past the screeners and into the hands of the editors.
After a few rejections I converted it into a 48 page graphic novel entitled Fuzzy Baseball. I put in the time to sketch out all 48 pages, and I submitted it to agents and editors who specialized in the emerging market of graphic novel/ picture book hybrids. The rejection letters became more encouraging, but they were rejection letters nonetheless. Then, I expanded it into a 56 page graphic novel and got more rejections. It sat on the shelf for a few years until I revisited it, and boiled it down to a 32 page picture book entitled Full Count. Still, there were no takers.
During this time I was making a living by illustrating chapter books (The A to Z Mysteries series, among others). An offshoot of this career is traveling the country, giving school presentations about my work as an illustrator, and an author (barely). In school libraries I kept seeing the graphic novel section expanding. It seemed to me that the majority of them seemed very similar, either in the anime style of Japanese Manga, or dark and post apocalyptical, or humorous in a very specific, retro-hip stylized manner. I thought there must be room for something that was funny, (but not retro hip) and action packed (but not violent), about BASEBALL, The American Pastime. What reluctant reader would not want to pick it up? Why couldn't I find someone to publish it?