The missile could clearly be seen flying past Rooney's shoulder.
Merseyside Police said on Tuesday that a 35-year-old man, from Huyton, had not been charged but summonsed to appear before magistrates in connection with the incident.
A police spokeswoman said: "Merseyside Police have summonsed a 35-year-old man from Huyton following an incident at Anfield in January this year.
"The man has been summonsed on suspicion of throwing a missile at a regulated football match.
"He will appear at Liverpool City Magistrates Court on 27 July."