Bremen, helping the team to advance to the first knock-out stage of the competition before losing to strong French side Lyon, who crushed them 10–2 on aggregate. His start in the 2006–07 season was not very successful either and he had to make seven Bundesliga appearances before finally scoring his first league goal of the season in Werder Bremen's quite disappointing 1–1 draw against underdogs Energie Cottbus at home. However, Klasnić suffered a kidney failure in early 2007 (see Illness and kidney transplant) and was out for more than ten months. In April 2008 he claimed that Werder's club physicians could have already detected the illness in 2002 and thus sued them in Landgericht Bremen. He also stated that he would not prolong his expiring contract with Werder since it would mean to be treated by the same medical personnel who had not detected his illness in time. On 14 May 2008, Werder Bremen confirmed that Klasnić was leaving the club. Nantes On 8 July 2008, Klasnić moved to FC Nantes where he was loaned, then he signed a four-year contract. After one very difficult season with just six goals in 28 games for him, Nantes was relegated in French Ligue 2. The next season, he scored four goals in just five games. Bolton Wanderers Klasnić signed for Bolton Wanderers on transfer deadline day of the 2009–10 season on a year-long loan deal, becoming Gary Megson's last signing for the club. "Ivan is a player who we have been tracking for quite a while. His goalscoring record is very good and he has an excellent pedigree at international level with Croatia and domestically in Europe." – Gary Megson. On 12 September 2009, Klasnić made his debut for Bolton in their 3–2 win over Portsmouth after coming on as a substitute for Sam Ricketts. One of his first contributions was to be involved in the move which led to the winning goal by Gary Cahill. His first goal for the club came in the 3–2 win against Everton on 25 October. He finished the season with eight Premier League goals. On 4 August 2010, Klasnić signed permanently for Bolton on a two-year contract following his loan spell with the club. and scored the first goal of his second spell in the 1–0 League Cup victory at Southampton on 24 August. His first Premier league goal after signing permanently was the winner