This used to be one of three baseball diamonds in the park. The area has gone through many “incarnations”, excluding the (very bad) idea of replacing the grass with synthetic fibers that look like grass.
I have good memories of couching Tee-Ball after work during the week on that diamond – giving the “team” freezies after the game. During the weekends, groups for friends would be “regulars” playing baseball.
Currently, it is a “hill” that used over the winter as a children’s slide – other than that, it is rarely used.
This is what the area could have been: