2mil over the next 3 seasons is league minimum, what the team HAS to pay him. But if he performs and is healthy in good faith the team likely gives him a fair raise over that minimum. Same with year 3. Decent players are getting 3 mil in their 3rd seasons. So with your offer of 7mil in those first 3 seasons if he performs well he'd likely gain nothing, or very little. But as you say it is a guarantee.
As for his arb seasons, Vlad Guerrero is getting over 14 mil in this his 1st arb season, I believe. So if Lewis is the player that was argued about being the top Twin prospect this year then he should easily make 40mil through arb. 13mil avg. You're offering him less than half.
The 3 FA seasons you offer him 37mil. He'd get in excess of 90-100 mil if he's the player you predict him to be. No way he'd even consider your offer. Unless he knew he was toast because of that knee. He would stand to lose 85mil with your offer, actually worse because losing those 3 FA seasons would knock down his FA contract as an older player. Very likely. I doubt he does become this player, because of that kne. I hope I'm wrong.