Morrison admits a confident Mulumbu will make all the difference to Albion's engine room.
"It is the second full season in the Premier League for him and he is not used to it," said Morrison to the WBA website.
"He is getting more fit and his confidence is growing again. That is what football is about, confidence. You can see that in everyone.
"Everyone is wanting the ball now and playing as a team.
"Youssouf was a huge player for us last season and on Saturday he played really well and got a goal."