San Francisco Giants catcher Buster Posey tops the list of the most popular jersey sales on MLB.com since the start of the 2013 season.
New York Yankees closer Mariano Rivera and St. Louis Cardinals catcher Yadier Molina round out the top three.
Fourteen of the top 20 players are All-Stars this season.
New York Mets third baseman David Wright and pitcher Matt Harvey are fourth and fifth, followed by Nationals left fielder Bryce Harper.
Yankees shortstop Derek Jeter, who made his season debut Thursday, is No. 7, with the top 10 rounded out by Baltimore Orioles third baseman Manny Machado, Los Angeles Angels of Anaheim centerfielder Mike Trout and Los Angeles Dodgers phenom Yasiel Puig.
Reigning American League MVP Miguel Cabrera was No. 12.