Lawnmower cutting uneven

Don't know if anyone has any experience with riding lawnmowers, but for about the last 4 months, my riding lawnmower has been cutting uneven.

I hit a large rock a while back and was missing a small strip in the middle of the deck, so I pulled the blades and noticed that one of them was broken on the end so I replaced them. Upon replacing them, the cut was much better, but there was still a small strip in the center that was uneven with the rest of the cut.

So I have been told that its possible that I have a bent shaft inside the spindle assy. Sound about right? How hard is it to replace those? Would it be easier to just replace the whole spindle assemblies?

I have a 2008 Husqvarna 46" mower with a 20 HP Kohler courage engine.

Your thoughts?