Mass Drain Confusion

I think I am doing the opposite of what GraceJones5 is doing! Our condo originally had a standard 60x30" tub. At some point, it was removed and a shower was put in. We have removed the shower and want to replace it with a tub. However, we've discovered that center of the drain is 16" away from the studs. This seems far to me. Is there a standard? What are our options for moving the drain (we have a concrete slab foundation)?

Many thanks in advance for your advice!
-Melissa

There is no standard. It was possibly moved when converted to shower, and may have to move back now. Breaking up a small piece of slab is not the end of the world. Post some pics for us for more help.