The Cubs placed de-facto closer David Robertson on the injured list without designation ahead of Monday's series opener against the Padres.
The Cubs recalled Frank Schwindel from Triple-A Iowa in a corresponding move. They also selected lefty reliever Conner Menez from Iowa and optioned Adrian Sampson there.
The Robertson move comes a day after Marcus Stroman went on the IL with no designation — moves indicating a relation to COVID-19.
Schwindel rejoins the Cubs a day after he was optioned to Iowa.
The Cubs added Menez in the minor-league portion of the Rule 5 Draft last December. In seven games (one start) with Iowa this season, he holds a 2.16 ERA across 16 2/3 innings.