Manager John Sheridan acknowledges he has plenty of work to do as he begins to put together his new-look Carlisle United squad.

A number of senior figures from the Cumbrians' side last season have left the club this summer, including Nicky Adams, Luke Joyce, Clint Hill and Mark Ellis.

That has left the new Blues boss with only 10 senior players signed-up for next season.

And the former Republic of Ireland international, who signed a two-year deal with Carlisle on Tuesday evening, is prioritising a goalkeeper and a striker as the first positions where United need to bolster their squad.

He said: "You are looking at a keeper, obviously. I think up top is another area.

"But we've only got 12 players [including youth players that have stepped up to the first-team]. So, listen, the squad size will be around 20-21.

"I have some work to do but I don't want players thinking they're comfortable and being automatic picks. I want players fighting for places every week.

"It's important we have a strong squad because it's not going to be about the XI that play. It's going to be about 16,17 or 18 players and then some young lads."

Sheridan, who has vowed to give youth a chance and has already set his sights on promotion, is also keen to get fans on board.

On Wednesday, he delivered an early message to supporters, securing a one-week extension to the club's early buy and renewal deadline for season-ticket holders, with the deadline initially set for today.

So far, more than 1,500 season tickets have already been sold.

"I'm different to the previous manager [Keith Curle]. I have my own ideas and I have a good record in this league, but I can talk and say all the right things," Sheridan said.

"But I want the fans to believe we can be really successful. I want them believing from day one that we will have a successful season and I really believe we will."

Of last season's squad, Danny Grainger, Cole Stockton, Gary Liddle, Mike Jones, Jamie Devitt, Hallam Hope, long-term injury absentee Jason Kennedy, Richie Bennett and Kelvin Etuhu are all on contracts that continue into next season.

Youth players Max Brown and Kieron Olsen have also penned professional deals with the Brunton Park outfit ahead of the 2018/19 campaign.

Sheridan, who led Chesterfield to promotion to League One in the 2010/11 season and guided Fleetwood to League One survival last term, admitted he already knows plenty about United's remaining players.

The no-nonsense boss has had three spells with Oldham Athletic, where he worked with centre midfielder Jones.

"I know quite a bit about them," said the 53-year-old. "I had Jonah [Jones] at Oldham, but I know most of the players.

"They have played against teams that I have managed before. There are some good players here.

"I'll identify where we need to strengthen and, hopefully, it will make us a stronger outfit."