The unknown is how his game can stack up to the pressure of the Ryder Cup, and how his emotions handle three days of the biggest frenzy in golf. The loudest cheer all week might be when Clarke's name is announced on the first tee.
Clarke returned to tournament golf at last week's Madrid Open after an eight-week absence.
A closing 72 earned him a share of 31st place, 15 strokes behind winner Ian Poulter.
"I didn't quite shoot the scores I wanted to but it was good to get back into a competitive arena," he said.
Clarke expects this week's matches to be played in a hard but fair manner, particularly since US players Tiger Woods and Chris DiMarco have also suffered family bereavements this year.
"With Tiger [Woods] losing his father and Chris DiMarco losing his mother, there are more important things than trying to win this week," he said.
"But in the end we're all professionals. We all want to win for our teams. As friendly as we are, I'm sure we're going to try to beat each other as soon as we stand on the first tee," he said.
"But I'm also sure that it will be in a friendly manner. At the end of the day, it's not life and death," he said.
Ireland is staging the Ryder Cup for the first time in the event's 79-year history, another motivating factor for Clarke to be playing this week.
"I really wanted to be a part of it," he said. "I was desperate to be here. For Ireland, this is huge. We had the Special Olympics two years ago and that was a huge event. This is even bigger."
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