Rosario has been out since Friday while Michael McKenry made his fourth straight start behind the plate Tuesday. Other top sluggers like Carlos Gonzalez, Troy Tulowitzki and Michael Cuddyer are currently on the disabled list for Colorado.
Outfielder Matt McBride has limited previous experience as a catcher in the Minor Leagues and the rosters are set to expand to 40 men Monday, but Weiss said the team would promote a catcher if Rosario lands on the 15-day disabled list.
"It's just too long to go without one," Weiss said. "But Matt can go back there and catch obviously. He hasn't done it during the season. He did it a lot during Spring Training for us, but we'd have to bring a guy in."
The only other catcher listed on Colorado's 40-man roster is Jackson Williams. The 28-year-old, who has never appeared in the big leagues, is currently batting .256/.353/.368 with four homers and 34 RBIs in 72 contests with Triple-A Colorado Springs.
Alex Espinoza is a contributor to MLB.com. Cody Ulm is an associate reporter for MLB.com.
This story was not subject to the approval of Major League Baseball or its clubs.