Arsenal manager Arsene Wenger says Danny Welbeck's groin injury restricted him to a substitute appearance in the defeat to Stoke City at the Britannia Stadium.
Welbeck was left out from the start before replacing Hector Bellerin at half-time as the Gunners staged a second-half comeback after Peter Crouch, Bojan and Jonathan Walters had given the Potters a three-goal lead at the break.
Santi Cazorla's penalty and Aaron Ramsey's goal gave Arsenal hope but they slumped to another defeat as Mark Hughes' side extended their impressive over the north London club.
England international Welbeck was a notable omission from the start against Stoke and Wenger says a groin problem forced him to start on the bench.
"Danny has played a lot, he had a little groin problem," Wenger explained. "He could have played. I rotated a little bit because I wanted to give him a breather.
"I had to respond at half-time unfortunately and it looked like he was alright. We have three or four strikers from game to game and not everybody can play.
"As Alexis has played every game, he has to dig deep in every game. At some stage you have to rest the players."
Arsenal's injury crisis in defence, which saw them without Laurent Koscielny, Mathieu Debuchy and Nacho Monreal has been accentuated by the imminent suspension of Calum Chambers after his second half red card.
It leaves Wenger with wafer-thin resources for the visit of Newcastle United next weekend, a predicament made all the worse after the French boss described his back-four as "soft".
"I think we were a bit inexperienced at the back," he said. "We couldn't play Laurent Koscielny or Nacho Monreal and we were maybe a bit soft to cope with what they offered.
"There's a lot of regret, we had given a lot. We showed great energy levels and a great response. The spirit of the team was fantastic.
"Defensively, we missed the start of the game. We gave easy goals away. We were not decisive in challenges.
"Once we were 3-0 down, we had a mountain to climb. We did climb, but were a bit unlucky I must say."