Zero, 40 starts for Samsonov would essentially be a 50/50 workload split. That isn't going to happen, especially since the split of starts through 42 games is something like 29/13. Even getting Samsonov to 30 starts this season would mean that the remaining 40 would be split 23/17 -- fairly close to a rotation from here on out. Now if Holtby continues his uneven performance AND the team starts to slump and is in danger of being caught/passed by multiple Metro teams, then maybe the organization turns to Samsonov to a greater degree. But until the organization's hand is forced by circumstances, what you get the rest of the season is probably pretty close to what you've seen thus far.
And while I'm at it, I've noticed something very interesting about Hagelin and Panik. Everyone generally seems to consider them pretty much of a bust, at least offensively, and are wondering how the 3rd line can be counted on to pull its weight. But to this point in the season, with both of them now having played in the low 30's in games out of the 42 the Caps have played, their +/- numbers are +7 and +8. Now I realize that there are real issues with equating +/- to quality of play, but it seems to be that the Caps are not being hurt at all competitively when these guys are on the ice at 5 on 5. And Eller is at +3, though he is used in more situations at 5 on 5 than they are (largely as a 2nd center on the ice when the Caps are trying to protect a lead in a close game coming down the stretch.) This must mean that, if the 3rd line is scoring only intermittently, then their opponents are scoring even more sporadically.