Please help identify a component on the logic board.

I am attempting a repair on a 2nd gen. iPod nano that I inherited. This iPod has seen some abuse (including what appears to be a botched repair job), so among other things, a component is missing from the logic board. Does anybody know what this component might be:

(see teardown picture here)

(part is circled in picture here)

• It's on the back (battery side) of the logic board
• It's directly to the right of the piezo speaker connector (opposite side as the memory IC)
• It's mounted vertically and has four pins (2 on top and 2 on bottom)
• It's about half way between the docking connector and the battery
• It appears to have been covered in cellophane tape
• It measures approximately 6mm x 3mm (0.24" x 0.12")

I am thinking, based on the trace sizes, connected capacitors, and location that this was a voltage regulator, power inductor, or diode pair.

Does anybody have any information as to what this part is?