The 27-year-old West Ham defender has just five senior caps to his name with a combination of injuries and former Ireland manager Giovanni Trapattoni's decision to ignore him for long periods having limited his involvement.
However, he has a seat on the plane for Wednesday afternoon's flight to Cologne and with interim boss Noel King's defensive options stretched for Friday's daunting World Cup qualifier against Germany by suspensions to Richard Dunne and John O'Shea - the pair will be available for Kazakhstan's visit to Dublin on Tuesday - he could be required.
That would bring an end to a frustrating period in O'Brien's international career, although he remains philosophical about the situation.
He said: "Look, I was injured for a couple of years really and the manager had come in and maybe had his players and had his ideas of a team, so when I came back and I was playing, he wasn't really putting me in the squads.
"But that time has gone now. It's a new manager, so it's just looking forward and hopefully I can feature somehow in the next two games."
O'Brien's chances may not have been helped by comments he reportedly made over Trapattoni's treatment of him, and while he admits he spoke "too openly" to a journalist, he insists that suggestions playing for Ireland meant nothing to him could not have been further from the truth.
He said: "I learned a really hard lesson then. It hurt me a little bit. Then I was injured for so long, so I couldn't really put it right.
"But look, it's gone now, it's in the past and I am here now, so hopefully I can play in the next two games."
O'Brien's club form will do him little harm as he attempts to force his way into King's thoughts, although he accepts that it is only what he does on the training pitch this week that will dictate that.
He said: "Hopefully I can train well and impress the manager and hopefully, I might get a shout.
"I have been playing, last year in the Premier League and the year before that in a good Championship team.
"But it's up to the manager. He has his own ideas on players and what he wants and how the players fit the system he wants to play.
"It's a different way of football, international football, to club football, so we will just see what happens."
Ireland will land in Germany knowing they cannot realistically make it to Brazil next summer, but determined to do all they can to avenge their 6-1 humbling by the Group C leaders at the Aviva Stadium in October last year.
O'Brien was not part of that squad, but he has been left in little doubt as to what the aim is for the return fixture.
He said: "There's a feeling after the last game and how it went to put it right. That's the aim.
"We are not going over there thinking we are just going to be beaten and it's over, we are going over to get a result and hopefully, we can."
- Sports & Recreation
- Giovanni Trapattoni