Now, it's time for Jack to prove he's worth the money.
The Cavs went after Jack this offseason knowing they needed some insurance behind the oft-injured Kyrie Irving. Cleveland had tried Donald Sloan, Jeremy Pargo and Shaun Livingston as backups last season, but none have Jack's scoring, passing and leadership abilities.
Now with Irving out once again, this time with a knee injury, Jack will be called upon to orchestrate the team's offense.
What Cleveland Needs From Jack
Asking Jack to pick up the 22.2 points per game Irving was contributing may be a stretch, but he can provide offense in other areas instead.
Throughout his career, Jack has been a solid distributor.
He owns lifetime averages of 11.0 points and 4.3 assists in 27.9 minutes a game. Jack has connected on 44.6 percent of his shots from the field and 36.1 percent from three in his eight-plus seasons.
Everything stat-wise from Jack isn't flashy, but it represents a significant improvement from Cavs' backup point guards in the past.
Now a reserve, Jack has had plenty of experience starting in his career.
Since coming into the league in 2005, Jack has been a full-time starting point guard for the Portland Trail Blazers, Indiana Pacers, Toronto Raptors and New Orleans Hornets. Heading into a January 4th game against the Brooklyn Nets, Jack had started 254 career games.
Cleveland needs all of this experience from Jack to carry over to his young teammates, raising all of their games as a result.
Be a Facilitator First
Jack has proven to be a good scorer in the NBA, but Cleveland needs his passing most.
The Cavs are 28th in the league in assists at just 19.1 per game. As good of a scorer as Irving is, he's far from one of the best distributing point guards in the league.
Jack needs to make more of an effort to get his teammates involved. With players like Dion Waiters, C.J. Miles, Tristan Thompson and Anderson Varejao, the Cavaliers have some offensive threats to get the ball to.
Too often this season, Jack has taken his own shots first before looking to teammates. His assists per 36 minutes (5.0) haven't been this low since 2008-09. Jack's assist percentage (percentage of teammate's field goals he assisted on while on the floor) this season is at 23.2 percent, also his lowest since 2008-09.
With Irving, he often runs too many isolation plays, which tend to leave teammates standing around and out of sync on offense.
Jack should be getting other guys going first before looking to score himself.
Stop With the Mid-Range Jumpers Already
This season, Jack hasn't been afraid to take, well, questionable shots.
For whatever reason, Jack loves the mid-range jumper. The problem with this is that it's his least efficient shot this season.
Over half of all of his field-goal attempts (149 of 297) come from the 8-to-24 foot area.
This is a dramatic increase from a season ago with the Golden State Warriors, where just 40.9 percent of his shots were taken from mid-range, compared to the 50.2 percent this year.
Shooting over half his shots from this range wouldn't necessarily be bad, if only he was making just a few more of them. From this range, Jack is shooting just 39.6 percent, his lowest mark from all six main areas of the court.
Jack isn't especially good at getting to the basket, and that's OK.
Staying out at the three-point line isn't a bad idea, as he's knocking down nearly 40 percent of his shots from deep this season.
If he does desire to do a bit of scoring, staying away from the mid-range jumper may be best for Jack right now.
One of the reasons the Cavs gave Jack $25 million was due to his strong playoff performance for the Warriors this past season.
In 12 playoff games against the Denver Nuggets and San Antonio Spurs, Jack averaged 17.2 points, 4.4 rebounds and 4.7 assists. He helped lead the Warriors past the higher-seeded Nuggets before forcing the Spurs to six games. He shot 50.6 percent from the field in those series and a sizzling 89.6 percent from the line.
The Cavs saw that Jack wasn't afraid to perform when called upon.
While he may or may not get to repeat this playoff performance with Cleveland this season, Jack needs to step up again as he did a season ago.
With Irving out and the team desperate for a veteran voice, now is the time for Jack to earn his money.
All stats via basketball-reference.com unless otherwise noted.