Is my clutch slave cylinder the problem?

One day while driving normally, trying to shift into 5th gear, i heard a "tink" noise and it wouldnt go into gear. I tried again and it felt like something was stopping me. And it's the same with every other gear. I pulled out the slave cylinder and I was wondering if it is normal for the piston to be completely out as far as it can go for it's default position. I manually push it back down, but it comes back out all the way. Is this normal or does it need to be replaced?