Lagares will compete for the center field job vacated when Manuel Margot was traded to Tampa Bay for reliever Emilio Pagán. Trent Grisham, obtained in a trade with Milwaukee, appears to be the front runner for center field, and Franchy Cordero also will be in the mix.
Lagares, 30, became a free agent after spending seven seasons with the New York Mets. He hit .213 with five home runs and 27 RBI in 133 games in 2019. He made 67 starts in center field.
Beckham, 33, was with Detroit in 2019, hitting .215 with six homers and 15 RBI. He started at all four infield spots, making 56 total starts. He also became a free agent after the season.
Pitchers and catchers report to Peoria, Arizona, on Wednesday, while position players report on Monday. The first full-squad workout is next Tuesday.
The Associated Press contributed to this report.