First-choice Pant last featured in an ODI in November 2022, a month before being involved in a near-fatal car accident, but he has since made a comeback to the national team and was part of their triumphant Twenty20 World Cup in June.
Pant also played in two of the three T20s against Sri Lanka last month but faces competition from Rahul, who has been solid behind the stumps and impressed during the 2023 50-overs World Cup at home.
"It's a tough call. Both are quality players, you know the abilities of both. It's not easy to pick a team when you have players like that," Rohit told reporters ahead of Friday's opening ODI in Colombo.
"That's what these two individuals are all about. They're match-winners in their own way.
"It's always nice to have (such) problems. When you discuss a lot about whom to pick, it means there's quality in the squad. I look forward to these problems."
Rohit handed over captaincy duties to Suryakumar Yadav after his retirement in T20s following their World Cup win in June but is expected to stay in the role in 50-overs cricket with the Champions Trophy scheduled for next year.
That tournament will mark another big test for India's new head coach Gautam Gambhir, who kicked off his tenure with a 3-0 T20 series win in Sri Lanka.
"We'll keep in mind what we want to achieve as a team but this is by no means preparation or practice (for the Champions Trophy). We want to play good cricket and get something out of the series. It's as simple as that," Rohit said.
"We don't want to think about trying this or that. Of course we want to try everything possible, but when you're representing the nation the quality of the cricket should remain the way it is and how we've played in the last few years.
"That's more important, more than thinking that it's a preparation so let's go out and chill in Colombo."
