Midfielder Liam Lawrence has suggested that Republic of Ireland manager Giovanni Trapattoni's insistence that the team play 4-4-2 could lead to problems in upcoming games.
Trapattoni's team currently sit second in Group B and face an important game at home to Macedonia on Saturday where a win would keep them involved at the right end of the table. But Lawrence feels the rigidity that comes with the 4-4-2 formation can be detrimental when the team find themselves behind in a game.
"I think the Russia game (where Ireland lost 3-2) was a prime example of that," he said. "The first 50 minutes we played 4-4-2 and got the runaround a little bit. When we changed, we nearly got back in the game. Sometimes it's done well for us, but I think now a lot of teams are playing with the three in the middle, two wide and one up front."
Aston Villa's Ciaran Clark, who has previously captained England at Under-19 and Under-20 level, could be in line to start his first competitive game for Ireland.
The issue of players making themselves available for the Republic of Ireland has led to questions from Portsmouth winger Lawrence - himself born in Nottinghamshire - about the prospect of Jermaine Pennant representing the Irish.
"It doesn't look good does it?" he said. "He is a good player. The only thing I know upsets us is when people are trying to juggle between England and Ireland. That's the only issue really."
A win for the Republic could see them end the day as leaders of Group B, depending on how Russia fare in their earlier match in Armenia.
Russia were strong favourites to win the group when the draw first took place, but after an unexpected defeat at home to Slovakia they have been unable to establish a big lead.
Armenia themselves are arguably punching above their weight in Group B, behind Ireland purely because of their head-to-head result in the opening round of matches.
Slovakia are also hanging onto the coat-tails of Russia, level on points with both Ireland and Armenia. They face a trip to Andorra who have lost their first four qualifying games, scoring only once in the process.