The decision not to start Tulowitzki came as somewhat of a surprise, because left fielder Carlos Gonzalez was out with a bruised right calf suffered Tuesday night. The Rockies needed a win not only to take the series, but to pull to 3-3 on their current nine-game road trip.
"With Tulo, I'm just trying to get a feel for how he's feeling each day," Weiss said. "It was my decision to keep him out today. I don't necessarily like keeping both those guys out at the same time, and it's a decision I came to after talking with him and just trying to stay out in front of some things."
Tulowitzki did not ask to sit. He had started all 20 games since May 4, and produced well in that period, batting .333 with a .439 on-base percentage, seven home runs, two doubles and 12 RBIs.
"I just think he just wants to give me a little breather. It's one of those maintenance things," Tulowitzki said. "It [stinks], but it's part of it. But we have talked about it from the beginning, and it's something that's part of our plan."
In the seventh inning of Tuesday's 6-2 victory, Tulowitzki did not have the gear it took to beat out a throw from Phillies third baseman Cesar Hernandez, who fielded a bouncer well behind the bag. Weiss didn't refer to a specific play, but he said he looks for signs that his three-time All-Star shortstop -- who, it was announced Wednesday, leads all NL players in votes for this year's All-Star Game -- needs to rest.
"That's what I do, try to keep an eye on him -- watch how he's moving, those types of things -- and act accordingly," Weiss said. "It's a good chance to get him a couple days in a row here."
The Rockies are off Thursday before beginning a three-game series in Cleveland on Friday.
Thomas Harding is a reporter for MLB.com. Follow him on Twitter @harding_at_mlb. This story was not subject to the approval of Major League Baseball or its clubs.