You could try it. I know of no reason why it wouldn't work.
Rip,
In PPST (2nd ed.) the explanation of the general concept regarding the split routine (p. 128-129) and the specific example on page 182 both propose a 4-days-a-week program.
I´m wondering if a split routine for 3 days a week would also make sense or if that would be rather unapplicable.
(For example, one could alternate between weeks with 2 days focused on pulling exercises and 1 day focused on squats and (bench-)presses and weeks with 2 "squat and (bench-)pressing" days and 1 "pulling day".)
You could try it. I know of no reason why it wouldn't work.
I did it for 2 months before I started SS. I was doing Push-Pull, Rest day, Squats/Deads, rest day, Push-Pull, rest, rest, repeat. The reasoning behind only 1 lower body day was I needed to improve my running FAST and couldnt recover from squating more then once a week. I made good progress on all lifts. So yes it works.