It's the hallmark of a great player that it's very noticeable that there is something missing when he's not playing.
So what does that mean for Sean O'Brien, when he is included in an Irish Team of the week despite not playing since last October? Is he that important for Leinster and Irish Rugby?
It'll be great to have him back in Blue and Green soon, but for the meantime his selection over Mike McCarthy in the Leinster team of the week while moving Jack Conan and Jordi Murphy out of their positions seems strange.
Munster and Ulster may have been on the receiving ends of hammerings, but that doesn't mean including 14 Leinster players that played, and one who hasn't over them.
Even when out injured @SeanOBrien1987 makes the @indosport #EPCR Team of the Week! #COYBIB pic.twitter.com/u0NEY9GKqD
— Marcus Ó Buachalla (@ohfadabee) January 20, 2015