The 24-year-old had earlier impressed West Indian all-rounder Dwayne Bravo with his exploits in the IPL for Gujarat Lions.
"He's a very, very good talent. He's sharp, he bowls quick and is somebody who can execute yorkers very consistently, and that's probably one of his biggest strengths," Karthik said on the eve of the first T20 between India and Sri Lanka here.
"He has a good slower ball as well. He has all the ammunition required to play the T20 format and I'm sure he will do really well," he added.
The latest pacer to come from Kerala, Thampi had a perfect IPL debut for Gujarat Lions, taking 11 wickets in 12 games with a best of 3/29 to be adjudged 'Emerging Player of 2017'.
He bowled yorkers at will and Bravo was quick to notice the youngster's talent.
"I would say he will get the opportunity to play for Team India in a year or so. He has the talent, obviously, but he also has a lot of heart, pace and the skill. He's always willing to learn," Bravo had said.
Within a year, Thampi was seen bowling to the likes of Mahendra Singh Dhoni and Rohit Sharma during India's training session on the eve of their three-T20I series opener at the Barabati Stadium.
With the Indian pace duo of Jasprit Bumrah and Hardik Pandya skipping the optional practice session along with Shreyas Iyer, Thampi was in the spotlight along with the likes of Mohammad Siraj and Jaydev Unadkat.
Thampi's allround show (four-wicket match haul and 60 runs) recently helped Kerala secure a historic Ranji Trophy quarterfinal berth.
Thampi has trained under Glenn McGrath and M Senthilnathan at the MRF Pace Foundation....