Cause as I keep saying. Adam and Lucas are forming a good partnership.
This is just silly.
However the main reason is cause the gap between Gerrard and Lucas was greater than Adam and Lucas.
this is partly true. the problem is that Adam likes to lie deep -- he is often abreast with Lucas instead of ahead. Lucas, by his inclination, is to look for the forward pass, because it's his job to win the ball and then pass it forward to a player who he thinks is running into position to start an attack. That's his job with brazil and that's his job here. SG is often this player because that's just how he rolls. Adam, on the other hand, likes to sit back and start his own attacks.
Basically, if you like, Adam is not the first player Lucas look to start an attack with because Adam lies too deep, so he rather passes it to somebody else.
Now, having said all that, it won't change your mind, since you already decided that Adam and Lucas are "forming a partnership".