Soto, who had missed time earlier in spring training after having a small bone removed from his left foot, left Sunday's game after his right knee locked up on him.
He was squatting behind the plate when he called for assistance because he couldn't move his leg.
"The cartilage was stuck in the joint," assistant GM Thad Levine said, "and that locked the knee up."
Levine said the injury occurred since Soto had returned from the foot surgery.
This is the second severe injury to a Rangers starter in 24 hours. The club announced Sunday that second baseman Jurickson Profar would miss at least 10 weeks because of a torn muscle in his right shoulder.
"We've lost two everyday players and there is no way to sugarcoat that,'' general manager Jon Daniels said Monday. "It is what it is. We'll look towards our depth and see where we go from here.''
Manager Ron Washington said he's not panicking.
"It's an opportunity for someone else," he said. "Soto came in on a mission and it's unfortunate this came up, but we're going to move forward."
Washington said the next eight days will determine who starts.
Chirinos has had a much better spring training than Arencibia. The question is whether the Rangers want to start a catcher who has played in only 33 career games.
"Chirinos has done everything. He has caught well, called a good game and swung the bat well," Washington said. "I feel like we have a formidable tandem to help our pitching staff get through innings."
The Associated Press contributed to this report.