Stewart, 22, the Rockies' top pick in 2003 First-Year Player Draft, saw Triple-A Colorado Springs manager Tom Runnells' number on his ringing phone. He had seen Jeff Baker suffer a mild concussion Friday from being hit in the helmet and face with a pitch in the Rockies' game with the Cubs.
By the time he had said hello, he'd added the two and come up with "Major League debut." Stewart batted eighth and played third base for the Rockies on Saturday night against the Cubs.
Stewart batted .304 with 15 home runs, 23 doubles and 65 RBIs in 112 games for Colorado Springs. The call came after Stewart went 3-for-5 with a double, an RBI and two runs scored against Tacoma on Friday night. It also came just as Stewart feels his swing is at its best.
"I felt that if they'd called me up at any point in the season, I'd have been ready," Stewart said. "I've felt good this year. I've been able to stay healthy and get the consistent at-bats that I haven't had in the last couple of years."
"Actually, the last couple of days or so I've felt really good, and I'm hoping to bring that up here.
Stewart battled hamstring and wrist problems at various points of his career in the Minors, but his potential for power has made him one of the most closely watched prospects in Rockies history.
He can pull the ball out of any park, but he needed work hitting to the opposite field to become a complete hitter. The left-handed-hitting Stewart said his opposite-way stroke is coming along fine, but it's something he'll always need to hone.
Ready or not, he'll have to show it.
With first baseman Todd Helton missing his third straight start and Baker on the disabled list, Stewart was inserted at third base and Garrett Atkins moved from third to first on Saturday.
"He's been on a nice run," manager Clint Hurdle said. "We rely heavily upon our Triple-A staff and our Minor League development people when we make these moves. There are a couple of other candidates that we've talked about that we want to look at, but he seemed to be the fit for the time and the issues involved here."
No broken bones: The arrival of Baker to the Coors Field clubhouse about 90 minutes before Saturday's game brought smiles and relief. CT scans did not discover broken bones.
"That's as good as we can hope for under the circumstances of what we're dealing with," Hurdle said. "Any time you see that happen, you go to a scary place. He seems to have come through it OK. He's pretty resilient."
Still waiting: Sunday afternoon's starter against the Cubs could be right-hander Tim Harikkala from Colorado Springs or it could be someone acquired from outside the organization. Hurdle declined to make an announcement before Saturday's game. One is expected afterward.
Injury report: Center fielder Willy Taveras was back on the bench with recurring quadriceps soreness. Taveras missed three straight starts, went 1-for-4 in Friday's loss to the Cubs, then reported soreness when he came to the park on Saturday. Hurdle said he would sit Taveras this weekend and look at playing him Tuesday on the road against the Padres before deciding whether to place him on the DL. ... Helton did some throwing, took some grounders and participated in batting practice before Saturday's game. ... Left-hander Brian Fuentes gave up one hit and struck out one during a one-inning injury rehab appearance for Colorado Springs on Friday night. He will work out of the Colorado Springs bullpen on Sunday.
Up next: The Rockies will host the Cubs in the finale of their four-game series on Sunday. The Rockies' yet-to-be-announced starter will oppose left-hander Sean Marshall (5-6, 4.17 ERA) at 1:05 p.m. MST.
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.