Lumsdon has spent five season as a first-team regular at Brunton Park
Carlisle United have released six first-team players following their disappointing season in League One.
Midfielders Chris Lumsdon, Lewis Neal, Luke Joyce and Jeff Smith, goalkeeper Chris Howarth and striker Danny Carlton have all been told they can leave.
However, the Cumbrians have offered new two-year deals to Danny Graham, David Raven, Tony Kane and Ian Harte along with Workington goalkeeper Adam Collin.
Former York midfielder Gavin Rothery has been handed a one-year deal.
Carlisle avoided relegation to League Two on the final day of the season, finishing one place and one point above the drop-zone.
The club's chief executive David Allen had promised a clear-out of the squad while manager Greg Abbott claimed he had "the basics" of a very good team despite their struggles this season.
Lumsdon, 29, joined the Cumbrians in the summer of 2004 following the club's relegation to the Conference.
Carlton joined Carlisle from Morecambe in July 2007
The Newcastle-born midfielder, who previously had spells with Sunderland, Blackpool, Crewe and Barnsley, made 182 appearances in five seasons with the club scoring 18 times.
Fellow midfielder Joyce, 21, has been unable to hold down a regular first-team place since joining from Wigan Athletic in 2006 and has had loan spells at Barrow and Northwich Victoria this season.
Former Bolton and Port Vale winger Jeff Smith joined Carlisle in a £60,000 from Vale Park in January 2007.
After becoming a regular in the side during his first season with the club, Middlesbrough-born Smith has endured an injury-hit season.
Ex-Morecambe striker Carlton began this season as a regular in the starting line-up but has spent the back-end of the campaign on loan at his former club and, more recently, Darlington.
Neal, 27, joined the Cumbrians during the January transfer window on a short-term contract following his release by Preston North End while goalkeeper Howarth has been unable to secure a regular first-team place since joining from Bolton in 2007.
The Cumbrians are hoping to tie-up new deals for top scorer Danny Graham and defender David Raven, who are both out of contract next month.
Graham, who was the subject of a failed £250,000 bid from Huddersfield in January, scored 16 times this season season but has gone 18 appearances without a goal since the start of the year.
Raven, 24, joined the Cumbrians in July 2007 from Liverpool where he was captain of the club's reserve team.
Right-back Kane, 21, has been offered a two-year deal following his release by Blackburn Rovers while former Republic of Ireland international Harte impressed in the eight games he played this season.
Graham is out of contract at Brunton Park next month
Goalkeeper Collin, 24, has been training twice a week at Brunton Park, with a view to a permanent switch.
Collin, who joined Workington in 2004, started his career with Newcastle United before loan spells with Doncaster Rovers and Oldham Athletic.
Midfielder Rothery joined Carlisle on-trial from Blue Square North side Harrogate Town following his release by York City last season.
The Cumbrians will wait until the current contracts of Michael Bridges at Hull City and Ian Morris at Scunthorpe run out next month before announcing a decision on whether they will offer terms to both players, who have completed loan deals at Brunton Park.
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