Sahih Al Bukhari Hadith Number 848

Narrated Nafi: Ibn Umar used to offer prayers (Nawafil) at the place where he had offered the compulsory prayer. Al-Qasim (bin Muhammad bin Abi Bakr) did the same. The narration coming from Abu Hurairah (from the Prophet (peace be upon him) forbidding the Imam from offering prayers (optional prayer) at the same place where he was offered the compulsory prayer is incorrect.

10  Call to Prayers (Adhaan)
Hadith number 848
Volume no 1
Chapter: 157 (The staying of the Imam at his Musalla (praying place) after (finishing the prayer with) Taslim)