Tulowitzki, who went 2-for-2 with a double and two RBIs, hit an infield chopper that charging Cubs third baseman Luis Valbuena could not barehand in the fourth inning. Tulowitzki generally saves beating out of infield hits for the season, and while he did not totally push it, he reached first base safely and would have had a chance to beat a throw.
"When I saw it come off the bat, I cringed a little bit, but he hasn't had any problems," Rockies manager Walt Weiss said. "It's a good sign.
"The plan is to peak when the bell rings in all aspects, for all our guys -- particularly a guy like Tulo, who missed time. We're watching him physically. When it's time to go, hopefully, he'll have peace of mind with himself and have enough at-bats."
After legging out the single, Tulowitzki slid into second base to break up a potential double play on Michael Cuddyer's grounder.
Thomas Harding is a reporter for MLB.com. Read his blog, Hardball in the Rockies, and follow him on Twitter @harding_at_mlb. This story was not subject to the approval of Major League Baseball or its clubs.