Wantz signed a minor-league contract with the Cubs on Saturday.
Wantz will report to Triple-A Iowa with his new organization. Before electing free agency last week upon clearing waivers, Wantz was lit up for five earned runs over 1.2 innings in his lone relief appearance for the Rays and posted a 7.04 ERA, 1.78 WHIP and 23:11 K:BB across 23 innings with their Triple-A affiliate in Durham.