Former Premier League defender Neal Eardley has joined the Imps on a contract until January.
Danny Cowley said: "I am delighted to be able to bring in someone of Neal's experience.
"In the two games he has played, he has shown what a well organised footballer he is.
"Technically and tactically you can see that he has played in the Premier League and will be a really good role model for our younger players.
"He's one of those that makes everyone around him five per cent better.
"What has impressed me the most is how much hunger and desire he still has."
Eardley, who appeared for Wales 16 times between 2007 and 2011, played for the Imps on Saturday in their 2-1 win over Walsall in Lee Beevers' testimonial and in a behind-closed-doors game this week.
The full-back began his career at Oldham Athletic, making over 100 appearances at Boundary Park.
He then made a move to Blackpool for a successful spell, which saw the Seasiders win promotion via the play-offs to the Premier League.
Eardley made 33 appearances during the 2010-11 season and did in the Premier League, a free-kick away at Everton.
Once his contract expired at Blackpool in the summer of 2013, the former Welsh international signed for Birmingham City on a three-year deal.
After a stop-start spell with the Blues, he linked up with Neil Lennon at Hibernian for a short spell, before spending last season with Sky Bet League One side Northampton Town.
Eardley becomes Cowley's second signing of the week following the recruit of Reading defender Rob Dickie.
The Llandudno-born defender will wear the number 23 shirt for the Imps.
