To make room for Richards on the 40-man roster, the Padres designated infielder Carlos Asuaje for assignment. Richards would immediately shoot to the top of the Padres' rotation, but he had Tommy John surgery in July. Unless he makes a quick recovery and the Padres are contending late in 2019, he's unlikely to pitch next season.
Still, the move makes some sense., and they'll essentially have Richards for $15 million that season long since cleared for full-go action.
Richards injured the UCL in his right elbow back in 2016 and had tried to comeback several different times without Tommy John surgery, using different technologies. None of them worked, so he finally broke down had the procedure last year. When he's right, he's a very good starting pitcher.
Since becoming a full-time starting pitcher (2014-18), Richards has made 86 starts. He's 34-25 with a 3.15 ERA (121 ERA+), 1.17 WHIP and 8.5 K/9. Control has been an issue at times, as he'd lead the league in wild pitches three times -- he even did so last season in only 76 1/3 innings.
Still, Richards could absolutely be a useful arm on a contender in 2020, his age-32 season. The Padres appear to be banking on just that.