By itself not. But is clear for nonbiased eyes, just read the history of Kievan Rus written by the third parties. Even in Polish language we have preserved word - Ruski, Rusin. In Russian language there is a distinction - Ruski chelovyek (Rus man) and Rosiyanin (Russian, Greater Russian) and so is Rossiya versus Rus. The title of Tsar was Tsar Sieya Rusi (tsar of all Russias) and Russian Imperator what was a different thing.
Didn't you and other fans of Putin claim a while ago that Ukrainian language is a mix of Polish & Russian and that Ukrainian nation doesn't really exist, but was invented by Germans ?
It is more complicated than that. The orginal Rus did not speak Russian or Ukrainian. They spoke the the local Rus[ian] dialects and the language of the court/church was more archaic than todays modern Rus[sian] languages. Literary Russian developed quite late and still locally you can find older dialects.
Ukrainian literary language was developed intentionally in westernmost Ukraine of XIX and includes elements of local Ukrainian/West Rus dialects plus Polish. The effort was to make Ukrainian as different from Russian as possible.
This effort was aided by Austrians who wanted to catalise the diveregence of Western Rus as a separate nation for obvious reasons. The final creation of a separate Ukrainian statehood was done by the Soviets who created Ukrainian republic in her present borders.
The prevalence of Russian language in eastern Ukraine is not caused by the Russification. It is rather reverse - the process of UKRAINIZATION initiated by Austria in Lvov region did not advance far enough to the east.