the mathis stuff seems pretty simple. He's 22 and he's in A-ball. He's the same age as Kurtz, Caglianone, Sal Stewart, Caminero, etc. If he's an actual prospect and a good hitter, he should be mashing without striking out.
Kurtz is obv a different level prospect, but he's the same position and the same age. When he was 22, he also had a good walk rate and a 30 percent strikeout rate. He was just doing in the MLB, hitting .290 with 35 bombs. Cags was striking out 20 percent of the time in AA and he can't make contact in the majors.