That cash will cover half of Richard's $3 million base salary in the final season of a $6 million, two-year contract.
The 35-year-old Richard was 7-11 with a 5.33 ERA in 27 starts for San Diego last season. He is 68-79 with a 4.46 ERA in 10 seasons in the majors with the Padres and Chicago White Sox and Cubs, with a National League-best 60.3 ground-ball percentage over the last four years.
Panas, 25, hit .232 with nine home runs, and 39 RBI in 105 games last season for the New Hampshire Fisher Cats in the Class AA Eastern League The left-handed hitter from Toronto was selected by the Blue Jays in the ninth round of the 2015 draft.
The trade was announced Sunday.