When he signed his $108 million extension it made him the 5th highest paid QB in 2013.
Had Dak accepted the 5th highest last year we would have saved $7 million per season ($53 million, 11.7% cheaper). That 7 million per, if given to someone else, would be the 10th highest paid player on this year's team.
Not blaming Dak, but he isn't worth either of those 2 numbers IMHO. Especially since, as shown above, it's not just costing the team an overpaid player (Dak) but also another above average starter somewhere else on the team.