Rios (groin) will head to Triple-A Iowa to begin a rehab assignment Wednesday.
Rios is likely to remain at Iowa at least through the weekend to stack up plate appearances after he had been on the shelf for the past week with a left groin strain. Before he was deactivated, Rios slashed .071/.235/.214 with one home run in 34 plate appearances with the Cubs while mostly serving as a bench bat.