Gonzalez, a potential All-Star hitting .295 with 10 homers, 42 RBIs and 41 runs, was sidelined for the Brewers series after suffering a bruised left knee in Minnesota.
He said he'd be wearing a knee brace on Tuesday.
"I ran on Saturday and Sunday," Gonzalez said. "Saturday was a little easier and Sunday was harder. But [Monday] was a really good day, because I got to rest and now I feel ready to go."
Manager Jim Tracy said if the Rockies had played Monday, it was uncertain if Gonzalez would have been ready to go.
"It afforded all of us a chance to take a day to catch our breath," Tracy said. "It gave Carlos an extra day, and obviously, he didn't miss a game. He's back in our lineup and he's hitting third and he has a very difficult opponent to deal with in Jon Lester -- not the easiest task in the world."
Lester, a left-hander, went into his start Tuesday for the Red Sox with an 8-2 record and a 3.13 ERA. Gonzalez's 24 hits and .324 average against left-handed pitching this season rank him second in the National League in both categories.