Ravichandran Ashwin has been an invaluable asset for India, especially in Test cricket.
Since his debut in 2009, Ashwin's countless match-winning efforts have seen him rise to become India's second-highest wicket-taker in Test cricket.
Earlier this year, he joined Anil Kumble to become only the second Indian to take 500 wickets in Test cricket.
Ashwin is clearly out of the reckoning in the T20I and ODI formats and with him turning 38 on September 17, Indian cricket's think-tank will be looking for a like for like replacement for him in the Test squad.
Former India wicket-keeper Dinesh Karthik reckons Washington Sundar is one of the top contenders to fill in Ashwin's shoes when the veteran spinner bids adieu.
'India are definitely looking for a next-gen off-spinner, as in last India 'A' series against England Lions, they tried three off-spinners in three matches: Pulkit Narang, Washington Sundar and Saransh Jain,' DK told Cricbuzz.
'Sundar is the front-runner behind Ashwin right now. He's done well in whatever limited opportunities he's got and I feel he will get his due first before going to anybody else,' DK, the former Tamil Nadu captain, asserted.
Sundar, 24, has played in all three formats for Team India.
He has already made 49 T20I appearances, and has further played in 22 ODIs. His last Test match came over three years ago when India hosted England for a five match series.
Sundar did, however, play a crucial role on India's last Test tour of Australia putting on an impressive all-round performance on his Test debut in Brisbane.
He picked four wickets (including three in the first innings), and scored a crucial 62 in the first innings to help minimise the run deficit in the first innings, eventually aiding India in clinching a memorable three wicket win, thus taking the series 2-1.
Other than Ashwin, India's regular spinners have been Ravindra Jadeja, Axar Patel and Kuldeep Yadav, the latter two have pushed Sundar down the ladder of reckoning with their consistent match-winning performances in the last two-three years.