Putin has a lot of killing to finish in Ukraine, and so one may ask, "Does he have the nerve and the means to finish the job in the Baltics?"
The answer: he has no choice.
No, it's not just Strelkov agitating against him: it's the future of Russia at stake: Russia must break the EU and make it submit to Russian patronage.
What are the mechanics? Let's review how this would work:
1) Russia invades Baltics.
2) EU inveighs and menaces yet does nothing.
3) Russia completes conquest.
4) Nationalists and anti-Brussels/Nationalist/syndicate factions in EU see the moral, intellectual, and spiritual vacuum in Brussels and in establishment EU elite, and they SWEEP elections or impose crippling protests that cause, this time, governments to crumble. The era of humiliation from ECB is over, and the Euro collapses (or is "redefined").
5) Putin backs a new, pro-Russian elite, and helps them insinuate themselves to the top positions of the EU elite.
6) In exchange for Putin's support, the newer, smaller EU will be expected to help "support" Russia and "expand trade" (extortion, I would assume), in addition to helping forestall US trade deals and impose protectionism on IP and goods from anti-Russian nations. This effort would find support from unions and nationalistic European groups, who fear American hegemony and Brussels' nihilistic and inhumane austerity.