Sehwag, appointed vice-captain for the series, steps into the shoes of Dravid, who suffered from cramps during his unbeaten knock of 103 in Ahmedabad [ Images ] on Sunday.
The team management has ruled out serious injury to Dravid and said he will sit out just a precautionary measure, since India have already taken an unassailable lead of 4-1 in the seven-match series.
But for Dravid's absence, the Indians would be in full strength with the return of Sachin Tendulkar [ Images ], Irfan Pathan [ Images ] and Harbhajan Singh [ Images ], all of whom were rested for the previous match in Ahmedabad which India lost by five wickets.
Coach Greg Chappell [ Images ] said he had faith in Sehwag's abilities to lead the side in Dravid's absence.
"He handled it pretty well at a short notice (in Ahmedabad when Dravid sat out). He is very much looking forward to it," Chappell said.
Also back in the team would be Mohammad Kaif, who was not included in the squad for the first five matches following an injury he suffered in the Challenger Series final last month.
Kaif said he was confident of doing well in the Rajkot game.
"I did not score lot of runs in the Duleep game but I spent enough time at the crease. I hope to do well," the Uttar Pradesh [ Images ] batsman said.
The Indian team has finalised the 12 with Kerala [ Images ] pacer S Sreesanth [ Images ] being rested but it was an anti-climax for young Punjab [ Images ] fast bowler Vikram Rajvir Singh as he was found to be unfit by the team's support staff on the eve of the match.
VRV Singh, chosen for the last two matches based on his impressive show in the Challenger Series, was diagnosed by physio John Gloster as having an "inversion injury to left ankle".
The youngster's hopes of making his India debut went up in smoke after being advised "a couple of weeks' rest", according to media manager Wg. Cdr. M Baladitya.
Vikram Singh had sustained a foot injury and missed the Duleep Trophy match for North Zone against Zimbabwe late last month.
"At the time of selection, the selectors were not aware of the extent of VRV Singh's injury. Basically, he has been advised rest," Baladitya said.
The selectors were expected to name a replacement for VRV Singh but it could not be confirmed if the player would be available on Wednesday.
The team management said Dravid, who remained in the dressing room during the Sri Lanka innings to receive treatment for cramps in Ahmedabad tie, skipping tomorrow's match did not point to any major injury worry.
"He is taking it a bit easy," the media manager said.
On Tendulkar, who had made a visit to a hospital in Ahmedabad prior to his departure to Rajkot, Baladitya said it was a "routine check."
"After his (elbow surgery), Tendulkar has been undergoing regular check ups. After the match in Ahmedabad, he had some free time and the facility was also there. So he met the doctors, there is nothing more to it," he said.
Sri Lankan captain Marvan Atapattu [ Images ] said he hoped to retain the winning combination of the fifth match but added that nothing had been finalised as yet.
Atapattu said the team looked to end the series on a positive note although winning three successive match against the in-form Indian team would be a "tough task".
"In the last game, we showed lot of character and belief in ourselves while chasing a target of 286. We want to end the tour on a high, and get the confidence going for the Tests.
"It would be ideal to have a 3-4 scoreline (after losing the first four matches) but India are a tough opposition. We rate them high in these conditions," he said.