If you are comfortable with a circular saw, it's a quick, easy fix. Pull the siding off, and cut the house wrap back. Lay out a rectangle that you will be removing, using a framing square. This would be from the center of one stud to another, 32" away. Take a cat's paw puller and remove any nails near the cut lines. Now set the depth of cut to about a 1/8th of an inch deeper than the OSB, or roughly 9/16th. Next is where it gets a little tricky. You may need to learn a saw technique called drop cutting. Basically, you place the front edge of the saw's shoe on the wall, and slowly lower the blade into the cut line, by rocking the saw back into the wall, until the shoe is tight to the wall. This allows you to start the cut. Keep a tight grip on the saw! You are stronger than the saw, and need to keep it under control, since it can bind and want to jump out of the cut. It's can be a bit unnerving at first, but hold tight, and keep a steady hand. Remember that you need to over cut, past the corners of the layout lines, since the blade needs to cut all the way through the OSB at the corners.
Once you remove the patch, thoroughly inspect the plumbing. If everything is good, re-insulate and install a new patch of OSB. nail the patch to the studs with 8D cement coated nails. Staple the house wrap up and tape the seams with the house wrap tape. Don't nail the vinyl tight, and nail in the center of the nail slots. You should be able to slip a dime under the head of the nail, when you're done. This allows the vinyl to expand and contract.
