Zhong Yao
Around April 211, Cao Cao ordered Zhong Yao to lead an army against the warlord Zhang Lu in Hanzhong Commandery and sent Xiahou Yuan at the head of another force from Hedong Commandery to support Zhong Yao. Gao Rou cautioned Cao Cao against such a move, saying that sending troops west could draw suspicion from the warlords in the area and cause them to revolt.