Think of it from his point of view - would he be better off playing regularly at Fulham, or waiting for injuries and suspensions to give him his chance at Saints?
With Lemina pissing around, Reed should be 3rd choice. Yeah it's a gamble because he might be sat on the bench a lot. But at the same time, one mild injury to either Hojbjerg or Romeu and Reed would really have an opportunity to make a name for himself. Both Hojbjerg and Romeu pick up yellows (and reds) frequently, and on this basis alone Reed would probably get into double figures. On top of that you have cup games, and like I said injuries. I reckon Reed could have been looking at 15-20 games had he stayed.
I guess Ralph sees JWP or Armstrong as able to play a deeper role, or this new fella. Bit of a worry though, considering our defence.

. I'm a doorman.