DEFENDER Kyle Hartigan is officially now a Hawk, crossing from Adelaide to Hawthorn for a future fourth-round selection.

Hartigan, 28, played 113 games – including the 2017 Grand Final – for the Crows since being selected with pick 14 in the 2012 NAB AFL Rookie Draft. 

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He played 12 games this season in a difficult rebuilding year for the club. 

While the key defender was an unrestricted free agent and could have walked to Hawthorn for free, the Hawks chose to trade so they didn't dilute their compensation for departed wingman Isaac Smith.

AFL.com.au previously reported Hartigan would take up a two-year deal, at a minimum, from the Hawks.

"The main reason in bringing him in is to obviously bolster the depth at the key defender position which he has played for a long period of time now at the Crows," Hawthorn footy boss Graham Wright told the club's podcast.

"Considerations such as whether we want to play Ben McEvoy in the ruck, James Sicily being out for probably most of next year and obviously James Frawley retiring, so, from that perspective, we felt like somebody else from a depth point of view was going to be really important. 

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"The Crows had offered him a deal as well, but his push was to get back to Victoria where he and his wife are from originally.

"So, from that perspective, it was a matter of the moons aligning for us and we think he can play an important role and give us options, really."