This is the 16632nd most frequent Polish word.
wrzuconego
"Wrzuconego" means "thrown in" or "inserted."
In this example, 'wrzuconego' acts to describe the boy who was included in the team, using a passive construction.
Chłopak wrzucony do drużyny zaczął się szybko integrować.
The boy added to the team started to integrate quickly.
In this sentence, 'wrzuconego' is the past participle of 'wrzucić' (to throw in) and describes the apple being placed into the basket.
Widzę jabłko wrzucone do koszyka.
I see an apple thrown into the basket.
Here, 'wrzuconego' used as a past participle modifies the book, indicating it was thrown into the bag.