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We report the discovery of a microlensing planet --- MOA-2016-BLG-227Lb ---with a large planet/host mass ratio of $q \simeq 9 \times 10^{-3}$. This eventwas located near the $K2$ Campaign 9 field that was observed by a large numberof telescopes. As a result, the event was in the microlensing survey area of anumber of these telescopes, and this enabled good coverage of the planetarylight curve signal. High angular resolution adaptive optics images from theKeck telescope reveal excess flux at the position of the source above the fluxof the source star, as indicated by the light curve model. This excess fluxcould be due to the lens star, but it could also be due to a companion to thesource or lens star, or even an unrelated star. We consider all thesepossibilities in a Bayesian analysis in the context of a standard Galacticmodel. Our analysis indicates that it is unlikely that a large fraction of theexcess flux comes from the lens, unless solar type stars are much more likelyto host planets of this mass ratio than lower mass stars. We recommend that amethod similar to the one developed in this paper be used for other events withhigh angular resolution follow-up observations when the follow-up observationsare insufficient to measure the lens-source relative proper motion.

MOA-2016-BLG-227Lb: A Massive Planet Characterized by Combining Lightcurve Analysis and Keck AO Imaging