It wouldn't even be that hard with minimal changes to OTL. There was considerable support for absorbing trans-Oder Silesia to Poland, but the rest of Silesia and much of Pomerania were not until fairly late really "on the table." Stettin, for example, which is practically most of the value of Pomerania, was only given to Poland to compensate for Stalin suddenly demanding Konigsberg, which would have been given to Poland.
Overall, the idea at first was to eliminate the East Prussia exclave, and then make Poland stronger with more defensible borders. A Silesia Oder border + a narrowing in Pomerania would accomplish this, though the straight Oder-Neisse had the same effect.