Lukas Jensen has completed a move to Millwall after a standout season which saw him statistically one of the best goalkeepers in League One.
The Danish keeper joined the Imps last summer and kept 19 clean sheets in the 45 league matches he started as City's No.1 - only missing out on the Golden Glove by one.
City rejected a number of approaches from the Lions, but an offer was eventually accepted after the Championship side met the club’s valuation.
City's director of football Jez George said: “It is always disappointing from an immediate sporting perspective to lose good players but this is evidence of how our recruitment model will grow and develop the Club. Lukas joined us on a free transfer 12 months ago, signing a two-year contract, and we sell him to a league higher knowing that otherwise he would leave on a free transfer next summer. As well as meeting our valuation, we also have a significant future interest in Lukas.
“Lukas will be difficult to replace but so was Carl Rushworth. However, the sales of two players with only 12 months remaining on their contract this summer will allow us to keep investing in young players, who will be future assets, as we have already with the acquisition of Rob Street and JJ McKiernan. Our ambition to consistently compete at the top end of League One depends on player trading, which enables us to continually strive to improve the aggregate of the squad, creating more depth and quality. That remains our aim in the last two months of this transfer window.
“Lukas leaves us with our best wishes. We knew this was one of two potential outcomes when we signed Lukas and unlike previous years, we are replacing a No.1goalkeeper having generated a profit in 12 months rather than a player returning to their parent club after a loan. We have proven our ability to develop young goalkeepers in our first team over the past five years with Alex Palmer, Josh Griffiths to Carl Rushworth and now Lukas. We will now try to add to this list, while knowing that we also have two long-term potential future No.1’s already in our building.”