Love steered his beloved Hurricanes to Super Rugby victory this season and has enjoyed sparkling outings against France, Italy and Ireland in the game-driving position.
The 25-year-old is one four flyhalves - five if you include Damian McKenzie - in the touring squad. There is competition amongst Beauden Barrett, Josh Jacomb and now the classy Mo'unga, who lands in the Republic on Friday.
Mo'unga has without doubt been the All Blacks' most complete ten since Dan Carter, so his arrival has left pundits wondering if the two-time Rugby World Cup medalist would leapfrog Love into the ten jersey.
But Rennie put that debate to bed.
"At the moment it's been Ruben's jersey, and he's going well, so we're happy with that," he told a press conference this week, as per Rugby Pass.
"It will be good competition, and all four 10s are really supportive of the decision. We're really happy with how Ruben's been going, with Damian, who we're predominantly using at 15 now, with Beauden and even Josh, who will get an opportunity on the weekend to start. So it's about creating depth in those positions, and Richie brings a lot of experience. But as I mentioned in the press statement, he's going to have to earn the right."
Love looked in fine form against the woeful Sharks on Tuesday, while Jacomb gets a run against the Bulls on Saturday.
Rennie went on to say that there's been good transparency between him and the players.
"I met with all four 10s yesterday morning, so I'd spoken to them before I'd even spoken to Richie," he continued.
"I just want them to understand that obviously Richie has been signed back to New Zealand Rugby. My job as head coach is to pick the best players available.
"I think when Razor [Scott Robinson] was obviously involved in bringing Richie home, he mentioned to Ruben about it. So even yesterday, Ruben was saying how good it will be to have him in. It's a chance to learn.
"With Damian injuring his ankle, he's not available for the Bulls. We're expecting him to be ok for the Test, but most of our 15 cover comes from 10s. That just reaffirms the importance of bringing someone like Richie in."