LONDON -- Arsenal captain Per Mertesacker says he has never played in a back three in his entire career, as the German veteran looks set to make his first start of the season in Saturday's FA Cup final against Chelsea.
Mertesacker could be an emergency solution for Arsene Wenger if Shkodran Mustafi can't play at Wembley, with Laurent Koscielny and Gabriel Paulista already ruled out of the game. Mertesacker had not played all season before coming on as a substitute against Everton on Sunday, and has no experience at all playing in Wenger's new back-three formation. Against Everton, Arsenal had already reverted to a back four after Koscielny was sent off.
"I haven't played ever in a back three, honestly. When I was young we started in a back four and that was my position from then on, for the last 15 years," Mertesacker said. "So everyone started from zero with that new system. [It's about] small adjustments, but what it comes down to is always knowing what the other is doing and giving him information that he knows what you're doing, or if you help him or not. Communication is the key in that system, even more."
That inexperience creates one more question mark around Mertesacker, who has also admitted he doesn't know if he's fit enough to last 90 minutes. The German has been back in full training since February after recovering from knee surgery, but hasn't even played a game with the under-23s until now.
"Sunday was pretty much a rehearsal for anything that could happen on Saturday. Match fitness is different. But there's no time to get another match for me. So you've got to be ready. If he calls my name, I have to be ready," he said.
Wenger might regret not giving Mertesacker a run-out with the youth team, with fellow defenders Carl Jenkinson and Mathieu Debuchy both having played for the under-23s recently. But Mertesacker said he also never asked for such a game.
"I thought, when I get a game for the first team it's enough for me. That was my mindset," he said. "So before Sunday I didn't have a proper game, just training sessions. I thought I can compensate with my experience. I've been here. And I felt like that [against Everton], I felt really good. And I didn't feel like I missed something by not playing another game. Even if I had played two or three months ago it wouldn't have made any difference. I just waited for that chance probably."
If he does play on Saturday, Mertesacker will come up against an old foe in Diego Costa, who got the defender sent off at the Emirates last season for a professional foul. The German said he has tried to learn from that mistake, and is prepared for the physical aspect of playing against Costa.
"You need to be ready and up for it. I think he's one of the main threats. He knows what he's doing, especially in the box. He's a scoring machine," he said. "But I won't do that on my own. I think we need to turn up as a team on Saturday no matter what happens."