"second most likely" is correct and can be used in written English.
It is used to express a secondary likelihood, for example: "The second most likely cause of the disruption was a power outage."
Novartis is the second most likely.
And UK citizens are currently the second most likely to donate to charity than any other country in the world.
At the online-betting sites, he's now considered the second most likely person to get the Republican nomination, behind Rubio.
UK participants were also the second most likely to believe that LGB people were "not accepted" in sporting culture.
The second most likely outcome, at least according to conventional wisdom, is a coalition between the CDU and the free-market Free Democrats (FDP).
Obama's "Dreams From My Father" is the second most likely book to be left behind in a hotel room in the United Kingdom.
"You won't see this, but if he comes out as the most likely or second most likely almost every time, it's still highly likely that it's him".
Tomorrow night, bookmakers have placed odds of 6/4 on Sam Callahan being given the boot, with Hannah Barratt the second most likely to leave at 7/4.
For all his flaws, he is at least the second most likely candidate to be prime minister after the next election.
Scottish crime writer Ian Rankin was the second most likely author to have his books donated to Oxfam's 685 shops, followed by James Patterson, Alexander McCall Smith and John Grisham, Oxfam said today.
Citing intelligence that the Pentagon is the second most likely target for a terrorist attack in the capital region after the White House, military officials want to shut the day care building next to the Pentagon by the fall.
