Albion boss Oscar Garcia believes the squad has not been deep enough to get into the top six.
The Seagulls could climb into the play-off zone if they beat Charlton at the Amex tomorrow, as Reading are not in action until Monday at home to Leicester.
Albion have been in the top ten since early December but in the top six only for a week in January.
Oscar will again be without the injured Will Buckley and Andrea Orlandi, who contributed 15 goals and 19 assists between them under Gus Poyet last season.
He said: "We are a good side and we can beat any team in this league but when we have to compete over a long season with a lot of games you have to have a deeper squad and we don't have that.
"With a deeper squad I am sure we would be in the play-off positions but now we have what we have and we are fighting with other big teams."
Albion and the other 23 Championship clubs met with the Football League in London this week to discuss proposed changes to Financial Fair Play regulations.
The main topic of debate was the advantage handed to clubs relegated from the Premier League by a £12 million increase in parachute payments to £60 million over four years since FFP was introduced.
QPR, Wigan and Reading, the three clubs relegated last season, are all currently in the top six.