I don't think that Lawrence is only putting in effort because it's a contract year.
He's just healthy.
This has been Lawrence's career:
2014 - Hurt most of the year as a rookie, no sacks
2015 - 8 sacks
2016 - Suspended then playing through injuries, 1 sack
2017 - Out of the gate on a blazing pace, with 3.5 sacks through 2 games.
The ability has always been there. The two seasons he's been mostly healthy and on the field he had 8 sacks and now is on pace to be in the top of the league if he keeps it up.
He's 25 years old.
If he manages double digit sacks this year and has turned into that kind of player and is healthy all year, you cannot let him walk. You franchise him for a year and see if he does it again, or you sign him long term if he is willing to take a modest deal (I can't imagine he would take a modest deal because double digit pass rushers in FA get MONSTER deals).