Sunderland are due to depart for South Korea on Monday for the Peace Cup pre-season tournament, however they could be without two first-team players.
Defenders Phil Bardsley and Matt Kilgallon are both injury doubts ahead of the pre-season tour and will be assessed before a decision is made on whether or not to take them.
One man who will travel to South Korea is young winger, Billy Knott.
The 19 year-old left-sided player spent the second-half of last season on-loan with League Two Wimbledon, making 20 appearances and scoring three goals.
Knott will be looking to use the Peace Cup as an opportunity to prove his worth to O’Neill ahead of the new season and potentially force his way into the thinking for the senior squad.
The tour will see O’Neill’s charges take on local out Seongnam next Thursday before facing either German side Hamburg or FC Groningen of the Eredivisie in the second game on Sunday.