SAN JOSE, Calif. -- Arsenal goalkeeper Petr Cech called the injury to Per Mertesacker "a big blow" and is calling on the likes of Calum Chambers, Rob Holding and Gabriel Paulista to pick up the slack.
Mertesacker injured his knee in training and didn't accompany the club on their U.S. tour. Manager Arsene Wenger confirmed at a news conference prior to Thursday's match against the MLS All-Stars (7:30 ET, ESPN) that the player underwent surgery and would be out for some months. Cech rued the loss of World Cup winner.
"[Mertesacker] is a great player, a great part of the team with his experience," said Cech in an exclusive interview with ESPN FC. "You cannot just replace a world champion winner just like that because obviously the experience of him, the games he played and he's one of the captains. That says it all.
"We will need to make sure that the players who will get their chances to play more, they will take it and they will rise to the occasion. Hopefully we will be able to start the season well and once he's fit he will come back [with us] in a position where we all want to be."
With Laurent Koscielny still being given a break after Euro 2016, and Gabriel recovering from tonsillitis, the Gunners have just Chambers and Holding to play centre-back on their American tour. Even after Koscielny returns, someone will need to step up when the season starts at home to Liverpool on Aug. 14.
"Now with Per out, the challenge and the possibilities for every central defender is bigger," said Cech. "It's up to [Holding] how he's going to play and how he's going to work. The same is true for Gabriel and Calum Chambers. This is their moment to show the manager they are up to the task."
The long-term injury to Mertesacker will put more pressure on Wenger as it relates to the club's lack of transfer activity. So far, Holding, Granit Xhaka and Takuma Asano are the only new arrivals. Meanwhile the likes of Manchester United, Manchester City and Chelsea have made multiple big-name signings.
Not surprisingly, Cech defended Arsenal's transfer policy.
"I think you need to be buy players you need, you need to buy players that will improve the team and not to buy players just for buying," he said. "That's the philosophy of the club. I've been here since last season and you can see that every time we bring in a player, it's a player we need, and the manager believes he improves the team.
"There is a core of the players who have been at Arsenal for years, and they know that is an advantage as well. People get to know each other, how to play together."
Cech did laud the acquisition of Xhaka, who was acquired from Borussia Monchengladbach for £30 million.
"[Xhaka] had been brilliant with Basel, he had been brilliant with Gladbach, so we bought a complete player who definitely improves our squad, and hopefully he will prove that on the pitch," Cech said.