Despite being top of the Premier League table, the Red Devils are expected to add to their squad after a disappointing campaign in Europe.
"The work goes on all year round but obviously intensifies as we come to the end of the season in terms of players," Gill told the club's official website.
"There's various contracts we've got to do, we'll look at some acquisitions and there will be some players who will leave. It's an interesting time."
United continue the defence of their title on Sunday when they host Everton at Old Trafford.