The 32-year-old native of Sweden has played in 770 games over the past 11 NHL seasons, all with the Vancouver Canucks. He is the Canucks' career leader in goals by a defenseman and was an All-Star during the 1998-99 season.
He received a seven-year deal worth $25.25 million. Ohlund will make $4 million in 2009-10, $4 million in 2010-11, $5.5 million in 2011-12, $5 million in 2012-13, $3.75 million in 2013-14, $2 million in 2014-15, and $1 million in 2015-16.
Walker played in 65 games for the Blackhawks last season, when he had one goal and a career-high 13 assists. Krajicek, who signed a one-year deal, had two goals and 19 points last season with the Lightning. Walker will make $1.275 million in 2009-10, $1.625 million in 2010-11, $1.9 million in 2011-12, and $2 million in 2012-13.
Ohlund played in all 82 games last season, finishing with six goals and 25 points. He has 93 goals and 325 points during his career. In 52 playoff games, Ohlund notched nine goals and 28 points.
The Lightning not only feel they improved their roster immediately but are also counting on Ohlund to be a mentor for Victor Hedman, the No. 2 overall pick in last week's NHL draft.
ESPN.com's Pierre LeBrun and The Associated Press contributed to this report.