Three players who could prove key for Tottenham against Manchester City on Sunday afternoon.
Indeed, Trippier has been in fine form for Tottenham Hotspur but Walker remains Mauricio Pochettino's first-choice right-back and, should he prove his fitness in training, will face City.
But that brings pressure. It's not that Walker is doing badly but the fact Trippier has now settled at White Hart Lane means the 25-year-old needs to justify his place in the Tottenham side.
As many pundits have observed, the Spurs centre-back has made a great start to life as Jan Vertonghen's stand-in - but this week provides Kevin Wimmer with the biggest challenge a defender could face in the Premier League.
Sergio Aguero is the best centre-forward in the top flight and best of the rest in the world behind Luis Suarez. Many Tottenham centre-backs have fallen to pieces against City - Wimmer would no doubt love to prove he is a new breed of Tottenham centre-back.
Harry Kane has nothing to prove in terms of quality but Spurs will need their front man to really lead against Manchester City.
If Vincent Kompany is out (or not fully fit), it'll be up to Kane to take advantage and instill fear in City's back four. Those in behind him, meanwhile, can gain confidence from his success - or be discouraged if he can't get the best of the Manchester City defence.