"Really, I was expecting before I got down here that those guys would play around the middle of Spring Training or a couple of weeks in," Weiss said.
The Rockies need both this season.
Gonzalez, a two-time All-Star, was leading the National League in home runs in July 2013 before a series of finger problems and chronic knee issues combined to lessen his playing time and effectiveness. He hit .238 with 11 home runs and 38 RBIs in 70 games last year before the surgery on his left patella tendon. Earlier in the season, Gonzalez missed time for surgery to remove a benign tumor from his left index finger.
Four-time All-Star Tulowitzki had a 1.035 OPS and was playing top-level defense until his 91st appearance, when he sustained his injury bursting from the batter's box on July 19 in Pittsburgh.
Gonzalez and Tulowitzki are the heart-of-the-order hitters in a lineup that many believe is one of the best in the Majors, with defending NL batting champion Justin Morneau and emerging productive players Nolan Arenado, Corey Dickerson and Charlie Blackmon.
Weiss plans to take Gonzalez's and Tulowitzki's playing time slowly, with much of it depending on how they feel each day, but he was pleasantly surprised that they are ahead of the original timetable.
"There were still a lot of baseball activities they hadn't performed, even when Spring Training started, so I was being very conservative in how I was looking at this spring," Weiss said. "When we incorporated baseball activity, they responded very well."
Weiss said that left-handed reliever Rex Brothers also will make his Spring Training debut Monday. Brothers' debut was delayed while he worked on timing issues with bullpen coach Darren Holmes during throwing sessions. Brothers slumped to a 5.59 ERA in 74 games last season, after putting up a 1.74 ERA in 72 games in 2013.
Weiss said Blackmon, who suffered a slight tweak to an abdominal muscle before games began, could join the lineup Monday or Tuesday.
Thomas Harding is a reporter for MLB.com. Read his blog, Hardball in the Rockies, follow him on Twitter @harding_at_mlb, and like his Facebook page, Thomas Harding and Friends at www.Rockies.com. This story was not subject to the approval of Major League Baseball or its clubs.