Bosh missed the team's West Coast trip after the All-Star break and the Heat lost two of the three games, including a 10-point defeat Sunday against the Los Angeles Lakers.
"Going through a time like that is always a difficult thing," Bosh said Tuesday afternoon. "I took some time to refresh my mind so I can come back a lot stronger."
The team initially said Bosh would miss two games, but he was not yet ready to return to the team following the funeral for his grandmother on Saturday.
"Family comes first before anything. He was able to come back today and that's when we want him back," teammate LeBron James said. "Before, if he wasn't ready, we didn't want him back."
"Very good to see him," Heat guard Dwyane Wade said Tuesday morning after Miami's game-day shootaround practice. "You realize how much you missed the guy. Had a little bromance moment for a minute. Wanted to hug him. But I didn't. I kept it cool."
Bosh had 20 points over 24 minutes in his return and had a message written to his grandmother on his game sneakers.
"She wouldn't have it any other way," Bosh said after the game. "She'd tell me, 'Go back to work. Work hard.' She lives on in our minds, so I came back to work."
The Heat had their two worst defensive rebounding games of the season with Bosh away as they struggled to handle bigger opponents. The Heat already had been concerned about their depth in the frontcourt and are attempting to add a veteran big man before the trade deadline next week.
"I always thought I was important," Bosh said earlier Tuesday. "I just try to help the team as much as possible."
Brian Windhorst covers the Miami Heat for ESPN.com. Information from The Association Press was used in this report.