West Ham boss Slaven Bilic bemoaned a slow first-half performance for the team's defeat to Leicester.
The Hammers had opened their campaign with victory at Arsenal last weekend, but they were beaten 2-1 by Leicester as goals from Shinji Okazaki and Riyad Mahrez proved enough despite Dimitri Payet pulling one back in the second half.
Bilic refused to point the finger at Reece Oxford, with the 16-year-old replaced at half-time by Pedro Obiang, and instead highlighted a rejected penalty shout on the stroke of half-time as Kasper Schmeichel and Diafra Sakho came together.
"We lost the game in the first half," Bilic said. "We were better in the second.
"The first-half performance was not down to Reece Oxford -- there were a few candidates I could have taken off.
"I remember the penalty incident and for me he could give a penalty. I saw it again and for me it is [a penalty].
"Maybe it was hard for the referee to see, but Schmeichel didn't get the ball and then spread his arms -- it could have changed the game, that was the moment you need something."
Bilic said the dismissal of goalkeeper Adrian, who kicked Jamie Vardy in the chest as he looked to backtrack having gone up for a late corner, "could have been seen as a red card."
He added: "I have no complaints about the referee's decision. I am more worried about the sanction and how many games we will be without him. The major part of the decision is if he did it deliberately or not and he clearly went for the ball."
The Spaniard is set to miss the next three games and may intensify West Ham's efforts to bring in QPR goalkeeper Robert Green.