He didn't play the full first team but he did play some of them, IIRC. Off the top of my head, I remember Van Dijk played in that one. Got bullied by Giroud.
The two-legged semi final is in between our league games against Liverpool and City. So, I don't know about starting our first team there. Plus, there's also an FA Cup tie in that period and we don't know when exactly the CWC is gonna happen.