Real number is $2M per season. The veteran minimum salary is $1,200,000. The Cowboys are only paying a salary of $1,250,000. They are also giving him a $375K signing bonus, and roster bonuses (paid weekly) totaling $375K. There are $1M in incentive clauses based on yards (1,100 yards minimum), touchdowns (10 TD's), and playing time (51%). Each of these only pays out if the Cowboys also make the playoffs.
The fact that he has a bonus for playing 51% of snaps means he will be the starter. But if he performs poorly, he could miss all of his incentives; and even if he plays well, he misses out on all the incentives if the Cowboys miss the playoffs.