Alvarez signed a minor-league deal with the Red Sox on Wednesday, Chris Cotillo of The Springfield Republican reports.
The 33-year-old utility infielder will report to Triple-A Worcester as he begins his tenure in the Red Sox organization. Milwaukee cut Alvarez loose over the All-Star break after he slashed .283/.397/.473 with seven home runs and 16 stolen bases across 257 plate appearances at Triple-A Nashville.