Honestly depends on what Critchley feels about the reserves that are yet to really get a run in the team. We've got plenty of players and cover in every position now, but the likes of Lubala, Woodburn and Sarkic have yet to really get going.
Extend Ballard, as you say, is a must for me.
After that, I feel it's a case of 1 in and 1 out . I like Lubala, just hasn't clicked for him yet, but the other two can go for me. Woodburn in particularly, if we can replace him with someone who can challenge for the AM/No. 10 role behind a central striker every week then I feel that would be a big upgrade. Anderson in there is fine, but if we could find a real gamechanger from somewhere that would be great.