His contract is one year with an option so it's really not that bad, but if he performs then you can hang out to him for 4 more years at a reasonable price. He improved across the board last year and I can get if you think that's just small sample, but his batted ball data also drastically improved. Much better K/9, HR%, GB% in 2020 than 2019. The only reason his ERA was so high was because his strand rate was the third worst in baseball among pitchers with at least 40 IP and his HR rate was 10th best in baseball. Just an anomaly, really. He's a guy I think you can buy low on from a bad team that is likely trying to cut costs.
I don't think the White Sox are really giving up anything of value here, but you may be right that they could offer less or maybe ask for $3 or $4 million in the deal.