Four days have passed since thee 2015 NCAA tournament field was announced, which means the madness has begun. There are 16 games on Thursday, 16 more on Friday and a total of 16 over the weekend in which the field for the Sweet 16 will be set. Do you sense a theme'All Your Bracket EssentialsDownload the Printable BracketPlay the Free Bracket ChallengeIn addition to the number 16, a great theme associated with March Madness is upsets. They are often hard to predict, but watching them happen is everything that makes sports great. This is a time of year when it doesn't matter Wofford is an underdog against Arkansas, because anything can happen.Here's a look at how the oddsmakers see things playing out in the NCAA tournament, as well as a look at some of the second-round games where upsets are brewing.Midwest: No. 5 West Virginia vs. No. 12 BuffaloWhen the brackets were released, the first No. 5 vs. No. 12 game that analysts circled for the lower seed was Buffalo over West Virginia. That tends to make me squeamish because when everyone assumes something, the opposite tends to happen.Yet there's something about the Bulls that is hard to resist. They are a battle-tested team, having played well against Kentucky and Wisconsin early in the season, and have a rising coach in Bobby Hurley.Talking to Zach Braziller of theNew York Post, Hurley acknowledged that the game against Kentucky, in which Buffalo led at halftime, was a turning point for him as a coach and mentor:I saw the talent we have and the competitiveness and the fearlessness the guys played with against that caliber of team. It benefited us [Saturday] night, when we played for a championship, to have played that game. Theyve been in big games like that against really talented teams. Im sure that night didnt feel that difficult to them.The key word in that comment is fearlessness, because that's what a mid-major school has to have in the NCAA tournament. It also helps that Buffalo has a quick-strike offense, averaging 75 points per game, and size with 38.4 rebounds per game.Bob Huggins has done a good job with this West Virginia team. His defensive pressure is a nightmare to break through, but it also leaves the Mountaineers vulnerable to opponents with speed.As Dan Greene ofSports Illustrated wrote in his team breakdown, Hurley's squad is dangerous because it can attack with three excellent players:(Justin) Moss, the MAC Player of the Year, is a 67, 240-pound hoss who can both score in the post and defend it. (Shannon) Evans, an all-conference second-teamer, is the Bulls other double-digit scorer (15.3 points per game) and a 37.0% three-point shooter. But Jarryn Skeete, his backcourt mate, is the teams most accurate marksman, making 39.3% of his treys while taking 154 of his 219 field goal attempts this season from beyond the arc.To win in the NCAA tournament, you must have size, speed and guards who can score. Buffalo has a great forward in Justin Moss, two proven guards in Shannon Evans and Jarryn Skeete and a head coach who has already figured out how to make all the pieces work.West Virginia is a volume scoring team, hitting a low percentage of shots to reach its average of 73.9 points per game. That's not the kind of squad you want to bet on in the NCAA tournament.Buffalo 71, West Virginia 64East: No. 3 Oklahoma vs. No. 14 AlbanyOklahoma vs. Albany is a sneaky game when you look into it. The Sooners are entering the tournament coming off an inconsistent 5-3 stretch to end the season, with a victory over Kansas being the most impressive of the bunch.Yet the Sooners never took off like they were expected to after being a Top 20 preseason team. They seemed to play down to their competition, losing to Creighton, Washington and twice to Kansas State. That's not a good trait to have in the Big Dance.Albany hasn't had an opportunity to play on the big stage this season, so Friday will be a coming-out party for this team. The Great Danes also fit the mold of an underdog team with a run in them thanks to two stars in Sam Rowley and Peter Hooley.Hooley has already jumped into the public conscience thanks to his game-winning three-pointer in the America East tournament final against Stony Brook less than two months after his mother passed away.Going back to Greene atSports Illustrated,the key to beating Oklahoma is slowing down the pace:AsKansas Stateshowed twice, if a team can put the brakes on the Sooners, they may put a stop to them: their offense drops from an outstanding 1.145 points per possession in transition to a pedestrian 0.835 in the halfcourt. They also dont compensate for offensive struggles by getting to the line, as their free throw rate ranks just 288th in the country.That plays right into Albany's hands because this team is not in a hurry to score. The Great Danes are a slow, methodical bunch that want to keep things moving at a snail's pace. Unless the Sooners can create in transition, this is going to be a long game.Albany 64, Oklahoma 60East: No. 4 Louisville vs. No. 13 UC IrvineThe first two upset picks featured teams capable of running in transition, which is not how Louisville plays. Frankly, Rick Pitino's team should look surprised whenever a shot goes in because the Cardinals are an awful offensive team.According to Kenpom rankings, Louisville is 98th in offensive efficiency this season. It's an excellent defensive group, ranking sixth in efficiency, but at some point you have to hit shots to win games.UC Irvine isn't a mid-major dynamo, ranking 135th and 91st in offensive and defensive efficiency, yet the Anteaters also rank 61st in team shooting percentage compared to Louisville at 211, viaESPN.There's also just the intrigue of wanting to see UC Irvine play as long as possible because it's got a 7'2" player inIoannis Dimakopoulos, who is the second tallest person on the roster behindMamadou Ndiaye (7'6").Ndiaye is the better player, averaging 10.4 points and 5.1 rebounds per game in 14 games this season. He's more of a role player than a star, but that size is a matchup problem for anyone inside.Louisville is so dependent on Montrezl Harrell, who plays better inside where Ndiaye will be waiting, that if he's not having a great day, this team just isn't going to score enough.Unlike the previous upsets, which were based on specific analysis, UC Irvine is more of a gut feel based on its strengths and Louisville's glaring weakness.UC Irvine 59, Louisville 57 Click here to read full news..