Betting company Ladbrokes currently has Louth & Horncastle as third favourite for where Boris will stand in 2015.
The constituency is 6/1, with South Cambridgeshire at 4/1 and Boris not standing for Parliament in 2015 as 2/5 favourite.
Sir Peter Tapsell will be announcing this evening that he is to stand down at the next election, set to take place in 2015, and there are rumours that Boris wants to return to Parliament.
The news comes after David Cameron said in The Sun newspaper this morning that he wants Boris to return.
“I want him to get back in Parliament,” the Prime Minister said. “It’s a bit like football...if you have got a great striker you want him on the pitch.
“He can complete as Mayor, or he can stay on as Mayor and come back to the House.
“I want him on the team.”