Wander Franco, a 20-year-old infielder considered the best prospect in the minor leagues, is set to make his major league debut for the Tampa Bay Rays against the visiting Boston Red Sox on Tuesday night. Franco hit .315 with seven homers and 35 RBIs in 39 games this season at Triple-A Durham. Tampa Bay has lost six straight, dropping a half-game back of the first-place Red Sox in the AL East. Meanwhile, the Dodgers and Padres square off again in San Diego with Los Angeles lefty Clayton Kershaw facing Blake Snell in a marquee matchup of Cy Young Award winners.