Rengifo was optioned to the Angels' alternate training site Thursday, Rhett Bollinger of MLB.com reports.
Rengifo was a relatively consistent member of the starting lineup early in the season, but he's seen his playing time drop recently as he's struggled at the plate. The 23-year-old hit .157/.283/.235 with one home run and one RBI over 18 games to begin the year, and he'll attempt to sort things out at the alternate camp and return before the end of the campaign.