After spending all of training camp learning the nuances of playing middle linebacker, Jack moved to weak-side linebacker for the preseason finale. He spent a month there and then switched to strong-side linebacker two weeks ago, before the Jaguars (1-3) beat Indianapolis in London.
Now, coach Gus Bradley expects him to stay there for a while. The Jaguars, coming off a bye week, play at Chicago (1-4) on Sunday.
''I just have to answer the call and continue to keep up with my studies,'' Jack said Wednesday. ''I'm going to try to make the most out of the opportunity and make the most of the position.''
Jack will officially play the ''Otto'' spot in Jacksonville's 4-3 defense. It's a strong-side linebacker who hovers near the line scrimmage and is mainly responsible for setting the edge against the run.
It's not the ideal position for Jack, a second-round draft pick from UCLA who is expected to eventually replace veteran middle linebacker Paul Posluszny. But it will get him on the field more often this season.
''He definitely has a big upside as we knew that when we drafted him,'' defensive coordinator Todd Wash said.
Jack might even supplant Dan Skuta in the starting lineup. Skuta sat out the victory against the Colts with a sore hip, but was not on the injury report this week.
Jack has six tackles and a pass defense in limited action. He played well against the Colts, especially considering he had just picked up the position.
''He's had to learn a lot, that's for sure,'' Posluszny said. ''When it's all said and done, he's going to have a great understanding of the defense because he's learned multiple positions. The good thing with this newest move, him being on the outside, his job will be very specific, so it shouldn't be an issue for him. He has the physical skills. It's about taking the time and learning the techniques he's going to have to use.''
The Jags believe Jack is the franchise's future middle linebacker. But since Posluszny has been better than anticipated in pass coverage, the team has been working to find other ways of getting him on the field.
Jack was considered one of the best coverage linebackers in the draft, but slipped to the second round because of uncertainty about his right knee. He tore a meniscus last September and missed the remainder of his junior season. He left school in early October to rehab in Phoenix.
The Jaguars checked his knee three times before the draft, and general manager Dave Caldwell felt comfortable enough to trade up two spots to grab him with the 36th overall pick when he starting falling.
Jack missed most of the team's offseason conditioning program because of NFL rules regarding college graduations, so he had a lot of catching up to do before training camp to get in better shape .
Getting a grasp on all three linebacker positions has been his problem since.
''At the end of the day, this is what I signed up for,'' Jack said. ''I feel like knowing all three positions gives me kind of like a whole perspective of the defense. It allows me to really see where everybody's at and kind of feel the space in and things like that. I think it's very beneficial. It just comes down to me applying myself.''
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