He made his IPL debut for Gujarat Lions in the 2017 Indian Premier League and was named the "Emerging player of the season".
[7] In July 2018, he was named in the squad for India Blue for the 2018–19 Duleep Trophy,[8] travelling through the flooding in Kerala to make the start of the season.
[13] In February 2017, he was bought by the Gujarat Lions team for the 2017 Indian Premier League (IPL) for ₹85 lakhs.
[16] On 17 May 2018, while playing for Sunrisers Hyderabad, Thampi conceded 70 runs in four overs against Royal Challengers Bangalore making it the most expensive spell in the history of Indian Premier League until 2024 where Mohit Sharma surpassed him with a 73 run spell playing for Gujarat Titans against Delhi Capitals.
Former India fast bowler and bowling coach of Kerala Tinu Yohannan described Thampi as "athletic" and "quite strong",[22] and added, "He's very deceptive.