Ramirez on the year is batting .206 with RISP, while Morrison is .146.
Ramirez hits third in the order, and Morrison hits fifth behind Giancarlo Stanton, who is hot.
"I just checked a couple of numbers," Guillen said. "[Morrison] struggles with men in scoring position. Hanley, too, is struggling with men in scoring position. In the meanwhile, we've got to get somebody to start swinging the bat a lot better behind Stanton."
Guillen noted he is not considering flip-flopping Omar Infante, who bats second, with Morrison.
"My third hitter is struggling with men in scoring position. My fifth hitter is struggling with men in scoring position," the manager said. "That's something we have to get better.
"I think the main thing for us is, LoMo has to get hot. I need someone to protect Stanton. We have a lot of confidence in him. We think he will come around."