What particular oil finish are you applying? Several years ago, I did a little experiment to see what glues would give me the most invisible repair joint in walnut. I cut and planed some small blocks of walnut and glued them using various glues and clear epoxies. Afterwards, I sanded the glued joints and applied various finishes to see how detectable the different glue joints were. (Titebond Type II was the winner) I used perhaps 8 or 10 different finishes including Tru-Oil, Linspeed, Watco Danish Oil, Clear Polyurethane, Minwax Oil Modified Poly, Sherwin Williams Spar Varnish, Tung Oil, Laurel Mountain Permalyn, Deft, and a couple others. I was struck by how much color difference these various finishes imparted to the walnut without the use of any stain whatsoever. I learned that it is very important to try your intended finish and/or stains on a piece of scrap that closely matches the wood you are going to finish. Otherwise, you may end up doing things over.
cpa's comment about using a clear sealer reminds me of the wood conditioners made by Benjamin Moore, Minwax, et al, that are meant to control the absorption of stain into wood, especially porous species. One of them might control the penetration of your desired oil finish.
