The Czech Republic midfielder was on the receiving end of a robust challenge from striker Gabriel Agbonlahor during the second half at Villa Park.
I don’t know is it broken or not, it looks bad
Rosicky, who came on for Serge Gnabry in the 69th minute, had to be replaced by Alex Oxlade-Chamberlain with four minutes of normal time remaining due to the injury.
“Rosicky has a bad nose, I don’t know is it broken or not, it looks bad,” Wenger told his post-match media conference.
On whether Agbonlahor had deliberately elbowed Rosicky, Wenger added: “Honestly I didn’t see the elbow, I have to watch it again.
“He [Tomas Rosicky] told me that he got the elbow but he himself doesn’t know if he did it on purpose. He doesn’t know.”
Wenger was also forced to substitute left-back Monreal in the 66th minute after the Spaniard picked up a metatarsal injury.
However, the Gunners boss revealed the north London side would assess the problem on Tuesday morning before making a diagnosis.
“I think Monreal is an accident but we have to check his metatarsal tomorrow morning because he got kicked on the top of the laces,” Wenger continued.
On the possibility that Monreal had broken a bone, Wenger added: “I don’t know.”
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