Bucky has finally been cleared to leave the infirmary. The shivering and mumbling are gone, but there's still something jarring and offset about him, even now. He's more serious, quieter than Steve thinks he's ever seen him. When Bucky smiles, and it isn't often, -even when he grins like a damned fool the way he used to- there's something small, forced, and sad about it. His expansiveness, his warmth… it's all just dimmed somehow.
Something Steve can't quite put his finger on is just wrong.
He tells himself that Bucky is just restless from inaction. His pride is hurt from having to sit in an infirmary when he he looked and felt fine. Bucky just needs something to distract him, make him feel strong and useful again. He just needs action and he'll be back to himself.
When Colonel Phillips mentions forming a squadron, Steve sees a chance and he takes it. They need a crack team who can find and destroy HYDRA. Steve has a few guys in mind, but there's only one he really needs a 'yes' from.
Bucky is already the best sniper the US Army has to offer; he's tough, reliable, and proven. He's also the one man on earth that Steve would trust his life to without a second thought.
There is never a question in his mind that if Bucky wants to be a Howling Commando, he will be.