Contracts have to be within these parameters. If you want to sign him for 5 years, the total of the contract would be 50 mil. Your options would be as so...
5 years @ 10
4 years @ 10.5
3 years @ 14
2 years @ 21
1 year @ 42
League Contract Parameters
<= $1m, 2 years
$1.5m - $5m, 3 years
$5.5m - $10m, 4 years
> $10m, 5 years (the overall limit)