Piper impressed many on the Foxes' right wing last season but was clearly looking to continue his career in the Premiership.
Saints miss out on Piper
Piper would have been an excellent addition to the Saints squad. Only 20 years of age in addition to having broken into a Premiership side. Piper could well have been a solution to Saints lack of attacking options down the right hand side. As skillful as Fabrice Fernandes was on Saturday, there didn't seem to be a lot of chances created from him.
Piper is expected to join the Black Cats for around £3 million.
Rupert Lowe said: "Naturally we're disappointed. It looks as if he's joining Sunderland instead but we have not completely given up hope.
"He's a nice lad and the door will be kept open for him because you never know what might be around the corner."
Despite their reputation for never buying anyone, Sunderland have now remodelled their right hnd side with the additions of Stephen Wright and now Piper. Both players were available for sums within Saints price range and it's my feeling could have improved our team.
With only a week left, Saints could well be stuck with the squad they have. While it contains a number of excellent players, there is the feeling that one or two positions need to be strengthened.