Is it permissible to delay prayer and combine Dhuhr and Asr due to extreme sleepiness resulting from work fatigue?

"Sleeping through prayer may or may not be a sign of negligence. If a Muslim sleeps before the prayer time begins, and sleep overtakes him despite his intention to wake up and perform the prayer, then there is no blame upon him. The Prophet, peace and blessings be upon him, and his companions once slept through the Fajr prayer during a journey and woke up after sunrise. The Prophet, peace and blessings be upon him, said: 'Indeed, there is no negligence in sleep. Negligence is only upon one who has not prayed a prayer until the time for the next prayer comes.'"