Smith is a battler but, like his fellow midfielders, has yet to really show out and does not, unlike Brown, score out of turn.
Sanchez' return has shored up the attacking support, and led to a couple of good goals, but the always-likely strikeforce, led by goal-grabbing Jeremy Brockie, is not getting enough good ball to seriously challenge opposing defences.
In Brockie, Louis Fenton, Tyler Boyd and Benjamin Totori, Herbert has livewire strikers capable of taking the game to the opposition. Belgian Stein Huysegems, early on, profited from good midfield service but his goalscoring has fallen away partially through the lack of good support from the players behind him.
Tomorrow's home game against Western Sydney Wanderers is another of those "must win" battles every team faces if they are to remain a contender. The Phoenix beat the newcomers 1-0 in their December 2 meeting at Westpac Stadium with Brockie's sixth goal of the season the difference.
While the Phoenix have fallen away since that victory, the Wanderers have picked up their game and hauled themselves into contention with now seven wins from 15 games and fourth place, just three points back from third-placed Melbourne Victory.
Under head coach Tony Popovic, the Sydneysiders return to Wellington as one of the form teams. They beat the Victory 2-1 on New Year's Day before going down 2-0 to leaders Central Coast Mariners.
With Boyd back from his one-match suspension, Herbert will consider changes, with the youngster likely to step back into the attack alongside Fenton and Brockie and Huysegems likely to join Totori on the bench.
A-League
Wellington Phoenix v Western Sydney Wanderers
Westpac Stadium
Tomorrow 4.30pm (live Sky Sports Highlights channel)
Referee: Shaun Evans