The 23-year old Canadian winger, from Okotoks in Alberta, has been rewarded for the huge impact he has made since arriving in South Wales in the summer of 2013. He finished his first season as an Osprey as joint top try scorer, with eight in 26 games, form that saw him selected by his peers in the PRO12 Dream Team for 13/14.
He's continued that form in the early weeks of the new season, with three tries in four matches, his physical, all-action style making a firm favourite with the Liberty Stadium crowd.
Previously a regular on the IRB Sevens Series with the Canadian side, he made his full international debut on the same day as his Ospreys team-mate Tyler Ardron, in a 28-25 win over USA in June 2012, and to date he has earned nine caps, scoring three tries.
His previous contract was due to expire at the end of this season, but the Ospreys have moved swiftly to secure his services beyond next summer. He becomes the 18th player to sign a new deal with the region during 2014.
Speaking after penning his new contract, Hassler said:
"I've been speaking with the coaches for a bit now, so to get it finally done and dusted feels pretty good. I can start to focus on the future now. You never know how these things are going to pan out, especially being a Canadian and somewhat unknown, but after last year it's nice that they recognised that I'm a big part of the team and want to keep me around for a couple more years.
"I hope to build on what I did last season. If I can keep on learning and improving with every game, that's the main thing, and I'm in the right environment for that. The games week-in, week out is the main difference to what I was used to before I came here. Back home I was doing the sevens stuff so I was training quite a big but you wouldn't have a tournament for four or five weeks at a time, you'd just train.
"Getting your body ready for games every single week and trying to stay mentally focussed is the biggest difference I've found. I'm getting there and hopefully with more experience under my belt that will get better and better."
Andrew Millward, Rugby General Manager at the Ospreys
"This is great news. We have been thrilled by Jeff's progress since he started with us in the pro game. We obviously saw real potential in him when we looked into potentially bringing him to the region and felt that his playing attributes and character would really suit the group and our ongoing progress.
"He does deserves great credit for his 'coachability' and ability to learn and adapt. Indeed, to be picked in the PRO12 Dream Team is a huge achievement at any time, but particularly so in his first season as a professional. We know he won't rest on his laurels though and will continue to strive for improvement, in himself and those around him. What is also exciting is the potential for future growth as he continues to mature and develop a broader understanding of his role and contribution to the team.
"Jeff is another example of the Ospreys taking someone who may be unknown to supporters and the Welsh media when they arrive but who thrives in our environment, which is focussed on development, and comes to the fore thanks to the support of everybody at Llandarcy. We are extremely proud of our development record and will continue to scour the market for players like Jeff who posses the right characteristics and ability to really make an impact in our environment."
Along with Hassler, 17 other players have signed new contracts at the Ospreys during 2014. They are:
Alun Wyn Jones, Sam Lewis, Ashley Beck, Eli Walker, Jonathan Spratt, Ben John, Ryan Bevington, Dmitri Arhip, Nicky Smith, Dan Baker, Dan Suter, Lloyd Peers, Hanno Dirksen, Sam Davies, Ross Jones, Scott Otten and Tyler Ardron.
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland