The Los Angeles Dodgers will be without Mookie Betts for the NL West team's series opener against the Chicago White Sox on Tuesday. Dodgers manager Dave Roberts revealed the reason behind the shortstop's omission from the lineup.While the reigning World Series winners continue their charge at the top of the NL West, former MVP Mookie Betts is struggling at the plate. However, Dave Roberts said Tuesday is a regular day off for Betts, calling it a "mental day." Hyeseong Kim is replacing Betts in the lineup.The All-Star slugger is batting .249 this season, but his numbers have dropped further in June. Betts is hitting .175/.241/.263 with a .504 OPS in 80 at-bats in his last 20 games.Despite his slump, Roberts is reluctant to move the former Boston Red Sox star to a different position.“I just can’t see that you go out there and stick him in right field tonight and he’s going to throw out two hits or three hits, or he goes to second base and he’s going to go on a heater,” Roberts said on Betts' struggles at the plate. “That’s hard for me to kind of imagine, but it’s a fair ask. I just don’t see that as the case.Mookie Betts dismissed idea of shortstop role hampering his offense While many believe Mookie Betts' role as a shortstop for the reigning World Series winner has hampered his productivity at the plate, the Dodgers All-Star dismissed those claims.“I mean, you can point to it and try to make it about shortstop, but it’s not about shortstop,” Betts said. “Because remember, last year, I was playing pretty well, playing at shortstop. I had no idea what I was doing. Now, I’m way more confident in how I show up and prepare each and every day. The shortstop argument can’t be it.”The Dodgers won 6-1 without Betts in the lineup on Tuesday. The second consecutive win in the series was headlined by Shohei Ohtani's solo home run, his 30th of the season.