SB 10.47.68

evaṁ sabhājito gopaiḥ
 kṛṣṇa-bhaktyā narādhipa
uddhavaḥ punar āgacchan
 mathurāṁ kṛṣṇa-pālitām
evam — thus; sabhājitaḥ — shown honor; gopaiḥ — by the cowherds; kṛṣṇa-bhaktyā — with devotion for Kṛṣṇa; nara-adhipa — O ruler of men (Parīkṣit); uddhavaḥ — Uddhava; punaḥ — again; āgacchat — returned; mathurām — to Mathurā; kṛṣṇa-pālitām — which was being protected by Lord Kṛṣṇa.
[Śukadeva Gosvāmī continued:] O ruler of men, thus honored by the cowherd men with expressions of devotion for Lord Kṛṣṇa, Uddhava went back to the city of Mathurā, which was under Kṛṣṇa’s protection.

The word kṛṣṇa-pālitām indicates that even though Uddhava became quite attached to the land of Vṛndāvana, he returned to Mathurā because Śrī Kṛṣṇa was personally displaying His transcendental pastimes there.