I disagree with some of the negative comments on here, especially those questioning Vinny's priorities. He has every right to want to captain his country. Something that only a small number of players get to do. He's heading into a World Cup where his team have a realistic chance of winning. Why on Earth would he not want to be a part of that? Why would he piss Martinez off and say he doesn't want to play in a smaller game - what if Martinez decides to drop him as a result?
You're talking about one of the most passionate, committed, ultimate professionals in the game right now. He's been our greatest club captain. Let's let him lead his country as best as he can, especially given it'll most likely be his last hurrah. We can't control Belgium's squad choice. What Pep can do is let him rest in games where we 'should' be comfortable (Brighton away, Bournemouth away). Managing his minutes on our end isn't ideal, but if it keeps him fit for the big games then surely it's worth it.
With Mangala and Tosin in the squad, and Pep's flexibility with formation we're more than covered at the back. Perhaps we could have swapped Mangala for a player who's more comfortable on the ball, but I think he'll offer us another option in rougher games such as your WBA/Huddersfields/West Ham/United etc.