The Baggies chief rang the changes for his team’s clash with Burnley on Monday with a host of regular starters missing out.
Kieran Gibbs – available after serving a three-match ban following a red card at Everton – was left out of the match day squad completely.
While regular starters Kyle Bartley, Semi Ajayi and Romaine Sawyers had to make do with a place on the bench.
“The players who played against Burnley did so because they showed me more than the others,” Bilic said.
“It’s all about competition on the training ground or on the pitch and it can always change in your favour.
“I thought that the team needed to be changed a bit.
“I saw a lot of positives in the first four games but I also saw some negatives as well.
“It was more that the players I put in deserved a chance than I dropped the other guys. The other guys deserved it.” With Gibbs not involved, Conor Townsend continued at left-back and helped the team secure a clean sheet in the goalless draw with Burnley.
And Bilic said Gibbs’ omission was nothing to do with his red card at Goodison Park.
“It was not punishment for his red card at Everton - no, no,” the head coach continued.
“That was horrible and I’ve told him that.
“But I would punish myself and punish the team if, because of that, I was going to say you have to wait to play.
“Training ground or the minutes you get in games - that’s it.
“Conor (Townsend) got a chance and he is doing well.
“Do I like Gibbo? Of course, I like him.
“But he has to show me that on the pitch, every day.”
Speaking at his pre-Brighton press conference, Bilic revealed Sam Field will be out for the next four of five weeks with a knee injury.
But he said the young midfielder is a great example of how performances in training can earn you a spot in the first team.
“If you asked me at the beginning of the season who was going to go out on loan I would have said Sam Field and he thought the same,” Bilic said.
“But he has almost played in every game - the competition is open and it is there.
“A few people were questioning why Sam Field wasn’t in the squad (for Burnley).
“He wasn’t in the squad because during the international break he got injured.
“He was one of the players that basically before pre-season he started from zero, and he proved himself and became a very important player for our squad.
“But he’s out, he’s injured.
“During the international break, we had a session and he twisted his knee a little bit.
“It’s nothing major, but it’s not a little bit so it’s a few weeks. It’ll be four or five weeks.”