Both players arrived at Parkhead in January, but the capture of the Irishman on a loan deal from Tottenham eclipsed Rasmussen's move from Danish side Brondby.
And while all the focus has been on Keane, who scored a hat-trick against Kilmarnock last weekend to take his tally to eight in eight games, Rasmussen has remained in the background and been used sparingly by boss Tony Mowbray.
Rasmussen has partnered Keane in Celtic's last two games, but is happy for the Republic of Ireland striker to enjoy the limelight while he takes time to get used to his new surroundings.