Jacobs was contracted to the end of 2013, but the Crows moved quickly to tie up the 24-year-old who announced himself as one of the competition's best young ruckmen last season.
An Adelaide spokesman said on Saturday contract negotiations with Jacobs were well advanced, but AFL.com.au understands the deal is already done.
Jacobs led the AFL for total hitouts last year (743 at an average of 31 a game), including a season-high 61 against Port Adelaide in round 15. His tap work was also extremely effective, setting Adelaide up to win more ruck duel clearances than any other team in last year's home and away season.
Jacobs finished fourth in the Crows' 2012 best and fairest and won the club's best team man award. He was also selected in the All-Australian squad of 40 and was widely considered one of the unluckiest players to miss the final team.
Jacobs crossed to the Crows from Carlton in the 2010 trade period (in exchange for draft picks No. 34 and 67) and soon established himself as Adelaide's No. 1 ruckman, finishing eighth in the Crows' 2011 best and fairest despite not playing until round five.
Jacobs has played 60 AFL games since joining the Blues from Woodville-West Torrens via the No.1 pick in the 2007 rookie draft.
He made his debut in 2009 and played 17 games for Carlton, but faced stiff competition for game time with the Blues' ruck options also including Matthew Kreuzer, Shaun Hampson and Robbie Warnock.
Sam Jacobs is a ruckman in NAB AFL Fantasy. He averaged 87.3 points in 2012. Register your team at our AFL Fantasy Hub.
Nick Bowen is a reporter with AFL.com.au. Follow him on Twitter: @AFL_Nick
