He knows why. The Rangers' offensive struggles have been more pronounced against left-handed pitching this season.
The Rangers went into Wednesday's game against the Padres hitting .192 with a .294 slugging percentage against left-handers. They were hitting .224 with a .427 slugging percentage against right-handers.
Part of the issue is the Rangers haven't faced many left-handed starters. When Richards pitches Thursday, it will be only the eighth time in 36 games the Rangers have faced a left-handed starter.
"I think it is a factor, but I still feel confident with our hitters against left-handed pitchers," Banister said.
It's no secret that left-handed pitchers have been tough for the Rangers' young left-handed hitters. Nomar Mazara, Rougned Odor and Joey Gallo are a combined 12-for-87 (.138) against left-handers, and Odor and Mazara don't have an extra-base hit against them.
The Rangers need their veteran right-handed hitters to carry them against left-handers, but they have struggled just as much. Mike Napoli is 3-for-27 off them, and Carlos Gomez is 3-for-24. Ryan Rua is hitting .217, and Delino DeShields is at .214.
The Rangers' best weapons against left-handers have been catchers Robinson Chirinos (3-for-7) and Jonathan Lucroy (7-for-21), but only one can be in the lineup at a time.
"What I'm seeing from my team is we've lost a lot of opportunities to produce runs because we are trying so hard," Gomez said. "We've got to get back to simple stuff. The biggest thing is we still believe in ourselves."
Banister has considered the possibility of sitting Mazara against left-handers but is so far resisting the idea. Banister said he expects Mazara to be in the lineup Thursday.
"This is a young player who I feel is ultra-talented," Banister said. "He needs to continue with the process. It's part of the growing pains of the big leagues. You've got to grind through it."
Hitting left-handers has not been an issue for the Rangers over the past six years. They have had a higher OPS against left-handers than right-handers in every year since 2010. That was the year before they signed Adrian Beltre, whose absent right-handed bat may be the biggest factor for the Rangers' struggles against left-handers.
Beltre is sidelined due to a strained right hamstring, and his return is not imminent. He is taking batting practice on the field but is not close to being able to run at full speed.
"I saw him today," Banister said. "He was in a good mood. Upbeat. To me that's progress, because the last time I saw him, that wasn't the case."
T.R. Sullivan has covered the Rangers since 1989, and for MLB.com since 2006. Follow him on Twitter @Sullivan_Ranger and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.