Sony's Shuhei Yoshida says he hopes Rise Of The Tomb Raider will eventually come to PlayStation 4, adding that he didn't know Microsoft had secured it as an exclusive.
Talking to Eurogamer about Microsoft's Gamescom conference, Yoshida said: "I was like, ah yeah, they're going deeper into the games already announced, you know, same kind of lineup, until they talked about Tomb Raider being exclusive.
"It's very interesting the way Phil Spencer said, what we are saying is, in holiday 2015 Tomb Raider is exclusive to Xbox. So it's open to interpretation. But still, we didn't anticipate something like this would happen."
Asked if he genuinely didn't know the deal had been done, he replied: "How could we know? [Square Enix] might have [told] our third-party relations team, but I didn't know.
Yoshida also told of the complaints he received from PS4-owning Tomb Raider fans following the announcement.
"Anything Microsoft announces, people complain to me as well," he said. "In general there are lots of people who are angry, who emotionally reacted to the announcement. Some people created an image saying negative things, like it was the end of Tomb Raider. It was a very emotional response."
Finally, when asked if he thought it would eventually come to PS4, he answered: "That question has to be asked to Square Enix and Microsoft. I hope the game will come out eventually on PS4. But how can I tell? Other than that cryptic message by Phil Spencer."
The news of Rise Of The Tomb Raider's Xbox exclusivity was announced during the Xbox Gamescom media briefing by Microsoft executive Phil Harrison and Crystal Dynamics head of studios Darrell Gallagher.
Xbox boss Phil Spencer later stated that the deal "has a duration", suggesting it may only be a timed exclusive or one subject to certain requirements, rather than an outright exclusivity agreement.