Alvarez will not play Monday night against the Colorado Rockies, the second straight game he has missed because of his sore knee.
"It was negative, so that's good news. His knee is sore. And he's not playing tonight. We're trying to hopefully get him ready to pinch hit. He's day-to-day so we'll have to see how he is," Baker said, according to MLB.com.
Alvarez made his season debut Friday after being activated from the injured list and is hitting .250 with a home run and four RBIs in two games.
He had been on the IL because of a positive COVID-19 test before summer camp.
Alvarez, 23, batted .313 with 27 home runs and 78 RBIs last season en route to Rookie of the Year honors.