If Vazquez is expendable and Durham has really taken his game up a notch, I'd say go ahead. We can't be sure about Durham; if he falls back and hits .267 again, you'd be getting too little. However, I think the signs we're seeing, such as a much higher walk rate so far, are all positive, and he's definitely a significant upgrade over Menechino.
Sounds like a deal that can help both teams. I'd go for it.