Speaking to the Official Club Website, the former Everton boss confirmed: "I can confirm that both Tommy and Shefki has chosen to look elsewhere for their football next season.
"We made excellent offers to both players, as good as we could make at Championship level but the lure of the Premiership has proven too great.
"I'm sorry to see them go and wish them every success in their future careers but now I know where we stand for next season and can start looking ahead.
"It's been a waiting game for us to see what decision the out of contract players made but we have had plans in place for a while and will now step them up to bring in new recruits.
"We are talking to a number of players and things are moving along but it's not a race. There's still plenty of time to get the squad I want in place before the start of the season - a squad that will challenge for a place in the Premiership."