Justin Smith has $2.1 million in unearned signing bonus money

When 49ers linebacker Chris Borland retired in March, he agreed to repay $463,077 in unearned signing bonus money. With 49ers defensive lineman Justin Smith retiring in May, he has more than $2.1 million in unearned signing bonus money. Specifically, the final year of Smith’s contract carries a signing bonus allocation of $2.186 million, arising from…