Seems like a lot of people think he's only competing for a center position. Giroux's played wing and his style fits wing better than a lot of these others competing for this spot. He's also shown some nice chemistry with Stamkos. These are all going to be factors when they're comparing him to someone like Getzlaf for instance, whose style of play is much more suited to center, which as many have pointed out has a lot more competition than wing.
I think the spot is still his to lose. People are making too much of his slump. 8 points in 16 games is bad, but not Gomez territory. The entire team is awful, the offense is the worst in the league. Obviously Giroux's slump is part of it, but the team's slump has a large effect on his production as well.
He's a playmaker, and as his critics like to point out, he's never broken 30 goals. When the entire team is snake bitten and can't find the back of the net, he won't be getting as many points. He's set up a ton of beautiful chances that go nowhere. Two players that have been a major part of his production, Timonen and Hartnell, have fallen off a cliff. They both only just got their first points. Playmakers will live and die with their team's performance, more so than goalscorers.
Not to excuse his bad play entirely though. He's been much less tenacious and hasn't looked like himself, other than this past game against the Oilers. I think he's still adjusting from the increased focus on him. Wouldn't have the same problem on Canada though with that stacked roster.