If Batum's max is same as Hibbert's, it would be 4yr/$58M ($14.5M per). From what I've ready, Minnesota likely can't offer more than $10M per season.
AFAIK, in the new CBA, the originating team can offer 5 years. So Indiana can offer 5 years to Hibbert, and Portland can offer 5 years to Batum. So they have leverage that way as well if they don't want to spend $14.5M per.