Sterling Hayden's voice

Watched this on DVD, attention was paid to something else briefly during Hayden's first on-screen appearance, all I heard were voices. Didn't recognize them, looked up and saw him talking and I was baffled. It didn't sound like Sterling Hayden at all. Sounded like he was getting over a rough cold, voice deeper and a bit hoarse.

25ish minutes later, when he goes over to Steve Lacey's house he's sounding more like his old self, although it's still not quite there.

When he's talking to Lacey at Cop HQ, Hayden's voice is back to what it was at the beginning.

Then he goes to the vet guy and his voice is better.

20 minutes later, he's back at the station talking like Vin Diesel. Same with his little speech near the end in the car, but not after he gets out of car. Obviously, you can tell which scenes were filmed first.