Striker Danny Welbeck could make the Arsenal squad for the first time this season against Leicester City on Sunday, but manager Arsene Wenger hinted on Friday that defender Per Mertesacker would not start against the league leaders.
Welbeck has been sidelined since April with a knee injury while Mertesacker last played for the Gunners in the 1-0 loss to Chelsea on January 24.
Leicester have great pace on the break and Wenger said he was likely to continue with his two quickest centre backs, Laurent Koscielny and Gabriel Paulista.
"I think sometimes I use a different formula," Wenger told reporters.
"Per Mertesacker is a great leader, but I have three centre backs and I adapt a little bit to their form, to the number of games they've played as well as to the opponent -- what is their strength and where they can hurt us."
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The Frenchman also confirmed that long-term injury absentees Santi Cazorla and Jack Wilshere would be challenging for a place in the squad in the next three to four weeks.
Arsenal snapped a three-game winless streak in the league when they beat Bournemouth 2-0 on Sunday.
"I believe there is still a long way to go," Wenger added.
"We didn't win for a while so of course the pressure on the team was a little bit stronger. It was very important for us to win on Sunday and I think we are back to our normal level.
"We have to get the momentum back. We want to find consistency in our results for the season."
