The MLS pair have both been linked with short-term Premier League spells during the North American offseason but Redknapp says they will not play at QPR this winter.
"To bring someone in like Robbie or Tim Cahill - you're taking them for about six weeks then you lose them at a time when you've got 10, 12 games to try to stay up. It's difficult," he told reporters.
"They'd improve any team, those two - they're fantastic professionals and great players. But I'm not close to doing anything with them."