The 24-year-old has missed 15 games through a thumb injury, his last appearance coming against the Orlando Magic on January 13.
But he is set to return on Thursday night, after revealing his thumb “felt great”.
“I was really happy about it,” he said. “So I’m ready to go.”
Capela was injured in a game against the Magic, as he left the game after 36 minutes.
Before the injury, he was averaging 17.6 points per game, and his absence was felt by the team, with Harden being let to pick up the slack.
Harden has been on fire this season, having scored 30 points in his last 31 games, but recently claims by Steph Curry have suggested he is unhappy with the way he is being forced to play.
The Rockets have also been without Chris Paul and Eric Gordon for large portions of the season.
And according to Curry, Harden doesn’t want to play the ‘heroball’ he has been forced while so many starters are out.
Harden told the Houston Chronicle last week that he was excited to see Cappella coming back, and that results will continue to come once their roster gets back to full strength.
“We have to be healthy,” he said.
“We haven’t been healthy all year long.
“That’s something I’m excited about.
“We had a lot of injuries, a lot of guys in and out of the lineup. Once we get a full roster, we’re capable enough to beat anybody.
“Defensively, we haven’t been great. We’ve been having some really, really big leads but can’t sustain them.
“Once Clint comes back, helps our defense, rebounding and our offense, I’m pretty excited about it.”