Ashwin wasn't part of the playing XI in the first two Tests.
Team India have preferred to go with a four-pronged pace attack for the first two Tests along with Ravindra Jadeja as the all-rounder.
Jadeja, a left-arm spinner, is yet to claim up a wicket in the series but he has played a couple of handy knocks with the bat.
"As far as Ashwin's playing is concerned, we're quite surprised to see the pitch," Kohli told a virtual news conference on the eve of the third Test. "I thought there'll be more grass on the pitch and it'll be more spicy and lively, but it wasn't the case. So, yeah, anything is possible.
"We always name our 12 and then on the day, we have a look at the pitch and what it could become on day three, day four and accordingly we will go in with the right combination."
"You don't want to disturb or interrupt a winning combination, especially when the team has achieved such an incredible win in the second Test and are even more excited to take the field again."
Having won the second Test at Lord’s by 151 runs, the tourists have taken a 1-0 lead in the five-match series. Openers KL Rahul (129) and Rohit Sharma (83) had led the foundation of victory with their 126-run opening stand on Day 1.
The India captain showered rich praise on Rahul and Rohit for proving the team strong starts in both matches.
"We hope that they continue in the same manner because the opening partnership in overseas conditions is so crucial to set up the right platform, from where the team can build on," Kohli said.
"That's something they provided us in both the Tests and hence we were in a winning position in the first game, and we ended up winning the second game after being put in."
(With Reuters inputs)