For the past five seasons, the Chicago Bulls have been a defensive juggernaut. Credit former coach Tom Thibodeau for that.

During his tenure, they were studs defensively, finishing first in points allowed twice.

Offensive success was another story. The Bulls averaged 96.5 points per game and finished 29th or worse in points scored two times.

After numerous clashes with the front office and disappointing playoff results, the defensive-minded Thibodeau was replaced by offensive schemer and NBA coaching rookie Fred Hoiberg.

The move brought the expectation that the offense would transform from a bottom of the barrel team to one of the best in the Association.

The combination of the talented roster plus a pass-happy, fast-moving offense left the bar set pretty high for the Bulls this season.

Failure to Launch

Through the first 25 games, it was apparent the system was not working. The Bulls had the fourth worst Offensive Rating, 98.3, better than only the lowly 76ers, Nets, and Lakers.

Questions abounded if the Bulls made the mistake of trusting the team to a novice coach. While the team was having some success in the win-loss column, the uneven performance on the offensive end dismissed any notion the Bulls could knock off the reigning Eastern Conference champion Cavaliers.

Since December 20, the Bulls have seemingly righted the ship, as they own a top-four Offensive Rating and are tied for fifth in points scored, behind the likes of San Antonio, Oklahoma City, and the Clippers -- in other words, some of the dangerous contenders for the title this year.

Considering the Bulls scored 100 or more points only 10 times in the first 25 games, their recent run of triple-digit scoring is even more improbable. In fact, it is so out of character that their nine-game streak with 100 plus points is the longest such run since 1995, the height of the Bulls' dynasty.

So why the sudden dramatic shift? What was the catalyst for improvement? The correct answer is two-fold.

First up, Jimmy G. Buckets rose to the occasion with his words and his game.

Butler Straight Ballin'

After a disappointing 16-point loss to New York on December 19, Jimmy Butler called out coach Fred Hoiberg for being too nice. Butler told reporters that the Bulls coach was too laid-back and not coaching hard enough. He continued to say that the freshman coach needed to get on players when they were not performing -- Butler included.

Many feared that a budding star chastising his coach through the media would have profound adverse effects on the team. In fact, the public complaint seems to have turned around the Bulls offense. Whether it is because Butler stepped into the role as the team leader that many teammates expected from him or that Hoiberg took the 26-year-old's words to heart, the exact reason for the improvement remains a mystery.

Ever since then, Butler has transformed into not only a vocal team leader but a star on the offensive side of the court. In the nine games since his outburst, the fifth-year pro has taken his game to an elite level. 

As hot as Butler has been over the last nine games, he has been absolutely dominant in the month of January. In the four games so far in 2016, Butler is third in the NBA with an average of 29.0 points. He also has 7.8 assists while shooting 51.3 percent from the floor. He is also asserting himself more, as he has been taking 19 field goal attempts per game and 9.5 shots from the charity stripe in the past four games.

Against the Raptors on January 3, Butler scored 40 points in the second-half to break Michael Jordan's long-standing record for most points in a half. Besides setting new franchise records, with 31 seconds remaining, he nailed a three-point shot to give the Bulls a two-point lead they would never relinquish.

While the 26-year-old has been on a scoring tear recently, his rise is not just points alone. On January 5, Butler set a career-high with 10 assists against Milwaukee. Then two days later, he repeated the feat against the Celtics. His all-around game is reflected strongly in his eighth in the league. This rating is an estimate of how many games above or below .500 a league-average team would win with that player as one of their starters.

Butler's play has been the main reason for the Bulls' scoring resurgence, but the second spark for the offense was a much-needed lineup reshuffling.

Going Big

The entire season, Hoiberg has been moving around players, in and out of the starting lineup, trying to find the right combination. In particular, his mixing and matching in the frontcourt was not providing consistent results.

Back on December 9, the groundwork was set for the offensive improvement when Taj Gibson took over the power forward spot in the starting lineup. Then on December 21, Hoiberg decided to go big by replacing Tony Snell at small forward with Nikola Mirotic. The combination of Mirotic, Gibson, and Pau Gasol on the floor at the same time have produced 1.13 points per possession, per NBAWowy.com. That is equivalent to a 113.0 Offensive Rating.

Mirotic has also proven to be the Bulls' most efficient player the past three weeks as the Bulls have a 116.7 Offensive Rating with the second-year forward on the floor and a 99.5 Offensive Rating when he is sitting on the bench, per NBA.com. Gasol has stepped up his game, too, with averages of 19.2 points on 47.8 percent shooting over the past nine games. 

Eastern Conference Contender

Even with Derrick Rose missing three games and Joakim Noah out the past eight, the emergence of Butler and rookie Bobby Portis has picked up the slack. When both veterans return, Chicago's depth will be the envy of the league.

The Bulls' current six-game winning streak has catapulted them to second-place in the East with a 22-12 record and only 2.5 games behind Cleveland. The league's leading rebounding team still owns a top five defense, regarding Defensive Rating, and now with an explosive offense to go with it, Chicago is a formidable contender in the Eastern Conference.