Sahih Muslim Book 4, Hadith Number 852.

Chapter : If the Imam arrives late and there is no danger of an unpleasant happening, another Imam can be appointed to lead the prayer.

This Hadith is transmitted by Muhammad b. Rafi’, Abu’I-Razzaq, Ma’mar, Hammam on the authority of Abu Huraira with the addition of (the word) “prayer”.