Ajayi was first called up to the Super Eagles squad before Christmas, but it is his form in 2019 that has made him one of the standout players in the Championship.
The former Arsenal trainee has been moved into a midfield role by Millers boss Paul Warne and has excelled, banging in six goals in the last five games. Ajayi believes working with the likes of Alex Iwobi and Idion Ighalo has helped raise his game.
“Spending time at training day in day out with top, top class players is going to help anyone improve, it makes me raise my game,” he said. “I have got different voices giving me different information that I can use and bring back to my game at Rotherham, it has been really positive.”
His recent call-up to the latest Nigeria squad was marked by him being listed as a midfielder, despite his original recognition earlier this season being as a defender.
That is testament to the job he has done in the Millers
Ajayi will contest a role for upcoming games against Seychelles and Egypt against the likes of Wilfried Ndidi and Peter Etebo.
"I feel very comfortable in midfield," he said. "I've played quite a few games there now and I'm understanding my role more and more every week.
“Richie (Barker) and the gaffer have been really good with me in terms of giving me information to fulfil the role.
“The last camp I went to I came on as a sub and played in midfield and then played 90 minutes at centre-half so the manager (Gernot Rohr) knows I can play in midfield.
“He has heard the gaffer here say a lot that I can play in midfield, they watch all of my games, so they will have seen I have been playing games in midfield and that is why I have been listed as a midfielder.”
He knows I can play multiple positions.
"It's always a massive honour to be called up by my country, I have been asked to represent them again and I am looking forward to the two games ahead.”
Ajayi is not the only international in the Millers camp as Will Vaulks made an impressive debut for Wales in their late 1-0 win over Trinidad and Tobago.
The midfielder gave a good account of himself and put himself in contention for next week's Euro 2020 qualifier with Slovakia, who have Millers goalkeeper Marek Rodak in their squad.