if you haven't cut the top out yet, you can slit the pattern and overlap the top of the sleeve pattern until it will fit inside the armsyce ( arm hole) of the pattern. If you have cut it out, you can make tiny pleats to take up the extra fabric. Keep in mind that the extra may not all be a design feature, it may be needed for ease of fit as well over the upper arm. This is the reason for my preference being to use tucks, pleats or easing to keep some of that extra fabric still in the upper arm even if i don't want the poof of the gathering.
If you don't want to gather because of technical difficulties try this: run a line of gathering stitches at at 6/8" and at 1/2", the gather and stitch at the 5/8" seamline. The double gathering rows tend to control any issues with gathering in small spaces.