Ryan Nelsen believes West Ham have issued a statement of intent by tying Winston Reid to a new deal.
Tottenham are keen for striker Shaquile Coulthirst to continue his development out on loan after his spell at Southend.
Former Sunderland manager Steve Bruce believes Paolo Di Canio paid the price for an outdated management style after being ousted by the Black Cats on Sunday night.
Di Canio's controversial reign proved a brief one as he parted company with the club after only 13 matches, his exit coming little more than 24 hours after a 3-0 defeat at West Brom left them rooted to the bottom of the table with one point from five games.
It is believed the Italian's strict regime, unpopular with his players, was key to his departure.
"You cannot manage in the Premier League these days through a fear factor," Bruce told talkSPORT. "You've got to be able to manage individuals.
"Man management has become more relevant in my experience than coaching.
"Once you get yourself in the Premier League, they're all good players and you've got to find a way of getting the best out of them.
"It's never been my style to criticise anyone in public and I'm disappointed for Paolo. He's a character. A manager's lost his job. Management is a lonely place and he's lost his job this morning. I feel sorry for any manager in that position. I've gone through it and it's not nice."
Bruce managed Sunderland from 2009 to 2011, taking over after the arrival of current owner Ellis Short, but working under then chairman Niall Quinn.
He believes the club's approach has changed since Quinn left and Short took over as chairman himself.
"When I first went there with Niall, everything we did was run through Niall and (Short) was a bit stepped back," he said. "Since he has become chairman he seems much more hands on now. I'm not privy to too much but when I was there all I did was answer to Niall."
Short's next task is to find a replacement for the man he appointed in a storm of controversy last year.
Critics rounded on Di Canio's alleged fascist sympathies, prompting the club to make a stout defence of their new manager.
After debates about his political views had died down, Di Canio kept Sunderland in the Barclays Premier League thanks in part to a memorable 3-0 victory over rivals Newcastle at St James' Park, but little else in his regime went right.
Former Sunderland captain Kevin Ball, currently on the club's coaching staff, steps in to lead the team on a short-term basis, with the club saying a permanent replacement for Di Canio will be announced "in due course".
Sky Bet immediately rated former Chelsea and West Brom manager Roberto Di Matteo as favourite, narrowly ahead of Gus Poyet, previously boss at Brighton.
The new man will face considerable challenges early in his tenure.
Sunderland recruited 14 new players during the summer transfer window, several for the first-team squad but others for the development ranks, but the new-look group is yet to gel.
Just as important as those who arrived were those who left.
Having already lost loan signing Danny Rose following his return to Tottenham, they sold goalkeeper Simon Mignolet to Liverpool and, on deadline day, Stephane Sessegnon to West Brom. It meant they had lost arguably three of their most effective players.
Liverpool, Manchester United and Swansea are next up in the league, offering little hope of an immediate turnaround in fortunes.Former Sunderland defender Michael Gray admits he was taken aback by the decision to part company with Di Canio and feels the Italian should have been given longer to try to turn things round.
"I'm surprised that Paolo's lost his job," Gray told Sky Sports News.
"You obviously don't get time in the Premier League to let the players gel, you've got to hit the ground running and obviously they haven't done that. It's been a disappointing start but I still think he should have been given a lot more time than he has been."
However, Gray, who played for Sunderland for over a decade up until 2004, also feels that Di Canio did not help himself with his public criticism of players.
"I think that when you come in front of the camera and you criticise individual players, it's something you've got to learn from, you can't do that in this day and age," he said.
"Dressing rooms can be very strong if you've got strong characters in there and Sunderland have certainly got that in the likes of John O'Shea, who's the captain at the club, and when you come out and criticise him publicly that filters through to the rest of the players in the dressing room and I think when you start losing the players it can make it very hard for yourself."