However, manager Joe Maddon doesn't believe Shelton is at fault for the team's struggling offense.
"I don't believe [the offense] is a reflection [of Shelton], I really don't," Maddon said. "I know what he does, I know how he does it. You watch the games being played, and the thing about coaches, it's about how diligent you are and the time you put in -- that you care. You can only give a player so much information.
"I believe when guys are successful consistently, a coach might be able to tweak you a little bit here or there and remind you about something, but what goes on internally is what really controls your success. And so, it's hard to pin that on a coach, and I really believe that."
When Maddon was asked if he expected Shelton back next season, Maddon replied: "We're talking."
"I mean, I'm not going there right now," Maddon said. "We'll be talking to all of our coaches at the end of the season."