Looks like a bowed wall stud. Is there a seam in the siding over or above the
center of the bulge? Doesn't take much water ingress to bow a stud. You'll
have to pop off that piece of siding, slice out the stud, and toenail in a new
one. Oh, yeah...first find the source of the water ingress :-)
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.