"I felt it grabbing me when we were playing San Diego, when I hit the double in my first at-bat," Gonzalez said of the injury, initially sustained last Sunday. "I tried to play through it. I wasn't feeling comfortable, so I rested a couple days."
CarGo made it through five innings Sunday, then missed starts Monday and Tuesday before playing Wednesday, when he said the circumstances never presented him with an opportunity to run at 100 percent.
Thursday's game in San Francisco, however, gave him an immediate challenge.
"I was just pacing myself until [Thursday], in my first at bat, when I hit that hard ground ball to second base," Gonzalez said before Friday's series opener against the D-backs. "I tried to avoid the double play, and when I tried to go 100 percent, that's when I felt it."
Gonzalez said he feels the hamstring grabbing behind his left knee, and doesn't feel comfortable playing with it at the moment, though he's optimistic about getting back on the field.
"It's a day-to-day type thing," Rockies manager Jim Tracy said. "There's a possibility it could be a couple days. I could tell he was favoring it badly when he hit the ground ball yesterday in the first inning. He was actually dragging his leg as he went to first base."
Gonzalez has been one of the most consistent players for an injury-riddled Rockies roster this season. He is hitting .304 (157-for-516) with 89 runs, 85 RBIs, 22 homers and 20 steals, while playing in 133 of Colorado's 150 games.
Though he's missed stretches while nursing injuries, Gonzalez has stayed off the disabled list and became the first Rockie to hit 20 homers and steal 20 bases in three seasons.
"I wanted to play the whole year without getting hurt," a frustrated Gonzalez said. "It was one of my goals, especially coming off of last year when I battled almost the whole second half with my wrist injury. I really want to be in the starting lineup every day. Finish what I started. Finish my season strong and stay in the game for the rest of the year."