"Nebraska is probably going to average around 40 points a game with that offense," Callahan said. "It is the tempo. You really have seen them continue to pick up the tempo. They don't quite run the no huddle as fast as Oregon, but they aren't far behind. It is only going to get faster this year with Taylor Martinez being a fourth-year starter in the system.
"They can really adlib this offense, and make checks and reads at the line of scrimmage that they may not have done the past couple of years."
Martinez will be protected by an offensive line that returns three starters, including first-team All-Big Ten guard Spencer Long, and will be surrounded by a plethora of weapons at the skilled positions, particularly in the backfield.
Although NU loses I-Back Rex Burkhead, who finished his collegiate career with 3,441 rushing yards and 30 touchdowns, junior Ameer Abdullah more than displayed the abilities to fill the role in extensive playing time last year.
Abdullah earned second-team All-Big Ten honors after subbing for the often-injured Burkhead, and finished with 1,137 yards and eight touchdowns.
Offensive Areas To Watch
Although there doesn't appear to be a weakness offensively for the Huskers, there is always room for improvement. Expect a breakout season from the NU passing game led by a trio of talented wide receivers.
"They probably have the best three receiver group in the Big Ten in [junior] Kenny Bell, [senior] Quincy Enuwa and [junior] Jamal Turner," Callahan said. "Those three receivers along with Martinez and Ameer Abdullah are as good of an offensive grouping as you are going to find."
Bell, a first-team All-Big Ten honoree in 2012, led the team with 863 receiving yards and eight touchdown grabs and is on track to become both the school's most prolific single-season and career performer at the position.
"Believe it or not, Nebraska has never had a 1000-yard receiver in school history and Kenny Bell has a chance at becoming the first," Callahan said. "Johnny Rodgers, who won the Heisman in 1972, holds most of the school receiving records but, with two years of eligibility left, Bell has a great shot at setting those records."
Enuwa (773 career receiving yards) and Turner (660 career receiving yards) augment Bell's big play abilities as reliable and explosive targets underneath for a dangerous and versatile offensive led by the always unpredictable Martinez.
"I think you'll see a lot of short passes because Enuwa and Turner are so good in space when they get the ball.
"They've said they want to throw the ball 25-30 times a game, but honestly they are still probably going to be a run first team. In a perfect world they are a 60-percent run, 40-percent pass offense. It is the ability of Martinez to keep the defense off balance with his feet and hit those passes that will make this team dangerous.
"This offense has really grown since the last time Michigan fans saw it in Ann Arbor, I think this offense is going to go far this year."
Nebraska completed an average of 16.6 passes out of 27.0 tries per game last season (61.5 percent). The last time the Huskers played at Michigan Stadium, Martinez connected on just 9-of-23 passes (39.1 percent) for 122 yards and a score in a 45-17 thrashing by the Wolverines in 2011.
In its four losses last year, Nebraska yielded an eye-popping 53.5 points per game and, in total, finished ninth in the conference in scoring defense at 27.6 points per game. If the young Blackshirt defense, which returns only four starters, is going to improve upon that abysmal number, it will start in the defensive backfield.
"Right now the real strength would be the secondary," Callahan said. "They return almost every cornerback on the roster. Both of their starters return, [senior] Ciante Evans is easily their top corner and they add a former Army All-American in [redshirt sophomore] Jonathan Rose, who was one of Auburn's top cover corners - he transferred and is eligible this year. They also return redshirt seniors Andrew Green and Stanley Jean-Baptiste. The list goes on and on."
Evans was an All-Big Ten performer in 2012 and Rose played in nine games as a true freshman for Auburn in 2011. Green started 12 games last season, and Jean-Baptiste's nine pass breakups last year was good for third-most in school history.
At safety, the Huskers must compensate for the loss of All-Big Ten safety Daimion Stafford, who started 14 games, made 96 tackles and intercepted four passes. Still, the young backend of the defense is a talented bunch.
"They have inexperience at safety, but they still have three or four pretty good players there, including [junior] Corey Cooper and [sophomore] Charles Jackson, who were both four-star recruits.
"There is a lot of ability back there."
Cooper saw action in all 14 games a year ago, recording 17 tackles, including 1.5 for loss, and Jackson appeared in 13 contests, making 11 tackles and breaking up a pass.
Defensive Areas To Watch
Nebraska will have to replace starters all over the front seven, including its leading tackler in linebacker Will Compton and its best defensive lineman in defensive end Eric Martin.
Fifth-year senior Jason Ankrah is the only returning starter on the defensive line, and Bo Pelini and Co. will be in desperate search of a true impact linebacker during fall camp.
"They have an experienced defensive end returning in Jason Ankrah, but other than him the defensive line is going to basically be all new," Callahan said. "They really have to get this younger group of defensive lineman up to speed quickly.
"It is similar at linebacker. They don't have a LaVonte David or Will Compton. The leading linebacker is David Santos, and I don't think he even had 15 tackles a year ago. There will essentially be three new linebackers on the field."
Luckily for NU, it opens the season with five-consecutive home games, which should provide an opportunity for the younger players to acclimate themselves on the big stage, and gain familiarity with football on the highest level heading into the Huskers' week 10 matchup with Michigan.
"The early portion of the schedule is crucial. They play five-straight home games in front of 91,000 people. That is going to allow the defense to hopefully develop some confidence and swagger with the home stadium behind them.
"They will have some favorable matchups against Wyoming, Southern Miss and South Dakota State where one would hope the defense would at least get comfortable before some of the bigger games on the schedule."
"I think the expectations are pretty high," Callahan said. "A lot of it has to do with the schedule. If you look at Nebraska's first eight games, other than the UCLA and Northwestern games, which will both be in Lincoln, the schedule is very favorable.
"Nebraska plays its first five games at home this year, and doesn't go on the road until week seven because of the bye week, and the first road games are at Minnesota and Purdue. I think the way the schedule sets up, especially with the offense that they return, they are pretty confident that the young defense can get going early on.
"I think anything less than a 10 or 11-win season will be a disappointment."