Martin Jol told The Mail On Sunday: "If Robbie wants to play for us, he will."
"I've told him that we have to fight his situation together. Robbie is a big part of our set-up.
"He can only get his best form by playing and that's why I am happy he is playing for Ireland. If you don't play 90 minutes, you tend to lose your fitness a bit.
"He's not like the old Liverpool 'super-sub' David Fairclough, he should be playing. But with players like Robbie on the bench you always have a chance. Nine out of 10 times he will score."
Former Republic of Ireland striker Tony Cascarino reflected on his own experience in The Times yesterday: "Playing well for 20 minutes meant playing badly whenever asked to play 90, which meant soon going back to playing for 20 minutes again.
"When Robbie started for Ireland against France last month he was lacking sharpness which could be attributed to an absence of full-match fitness. Even if you train all week, it makes a huge difference if you don’t play much come the weekend."