The England international is reportedly close to a move to MLS side Toronto FC, while his fellow forward has been recently included in Spurs' first-team squad by Tim Sherwood
The former Spurs boss has been linked with another raid on White Hart Lane to bolster his attack at Loftus Road - which has been largely reliant on 12-goal Charlie Austin this term - after previous loan moves for Tom Carroll and Beniot Assou-Ekotto.
Defoe is reportedly set to join Toronto FC, but the MLS season does not start until March and it has been suggested the striker could make a short-term switch to QPR in the meantime.
Redknapp is also an admirer Kane, who was praised by Tim Sherwood after coming off the bench in Tottenham's win at Manchester United, but does not expect either player to drop down to the Championship.
"I would love [Defoe] on loan for a couple of months but I couldn't see a possibility of it happening and we've never discussed it," he told reporters.
"Harry came on at Manchester United so I think he's in Tim's plans. I'd be surprised if Tim, if he loses Defoe, [lets Kane leave] as he'd only have two strikers."