But the experienced forward insists he is prepared to stick with it in the hope of catching manager Alex McLeish's eye.
Phillips told the Birmingham Mail: "I'd imagine further chances will come off the bench. I think the manager has already said I won't be starting many games this year so I've just got to keep myself bright and keep that enthusiasm for when I do come off the bench. All I can do is use reserve games to try and get my match fitness. Hopefully that will stand me in good stead for when I do come off the bench.
"Where I am at the stage of my career, the amount of first-team games that I've played, for me to play in the reserves, yes, I'll be honest, part of me finds it difficult but that is part of the game.
"I'd rather be playing first-team football but that is limited options, so reserve games are the games when I've got to try and get my match fitness. I'll continue to do that."