Ohio State recently became the first unanimous No. 1 team in the history of the Associated Press’ preseason poll (Photo by Kevin C. Cox/Getty Images)

Ohio State recently became the first unanimous No. 1 team in the history of the Associated Press’ preseason poll. Since Urban Meyer brought the Buckeyes to No. 3 in the AP’s end-of-season rankings in 2012, his first season with the program, the team has yet to rank lower than fifth in the preseason poll.

After a 42-20 lambasting of Oregon in last season’s inaugural College Football Playoff national championship game, the team returns 16 starters and, per Vegas Insider, are the 9-to-4 favorites to win this year’s national title.

Meyer’s roster is brimming with NFL-ready players on both sides of the ball: Some analysts project five Buckeyes to be taken in the first round of the 2016 NFL draft.

At some point the conversation must be broached: Can any team stop the Buckeyes?

There are three teams with a chance, but only two are on Ohio State’s regular season schedule.

Virginia Tech

College football fans only have to salivate for four more days before the Buckeyes face their first test: a prime-time matchup in Blacksburg. Under Frank Beamer, the Hokies have won 77.2 percent of home games since 1987.

A season ago, a Michael Brewer-led Virginia Tech squad upended the Buckeyes 35-21 in the Horseshoe, creating the only stain on Meyer’s otherwise unblemished record.

The Buckeyes have lost three games over the past three years—against Virginia Tech, Michigan State, and Clemson— and each came to an elite defense that was particularly deft at disallowing methodical drives, or drives that run 10 or more plays. The ability to prevent methodical drives, which keep defenses on the field for longer periods of time than quick-strike offensive attacks, has correlated to success in recent years. For example, the top four teams in methodical drive prevention last season amassed a combined 32-14 record last season, and each won their respective bowl game. More often than not, methodical drive prevention means a defense is converting third-down situations and forcing punts, rather than allowing either explosive drives or long, stamina-emptying possessions.

The season Michigan State and Clemson beat Ohio State, they were ranked ninth and 14th, respectively, in the ability to stop methodical drives. When Virginia Tech beat Ohio State in 2014, the Hokies were ranked third in the country.

While there’s currently a premium placed on offensive firepower in college football, only one of the aforementioned teams that beat Ohio State had a scoring attack that ranked in the top 100 in the country.

Last season, Virginia Tech ranked second in the nation in Football Outsiders’ Defensive Fremeau Efficiency Index metric, which measures how successful a team’s defense was over the course of a season when adjusted for how deft the opposing offenses were and presents a more realistic depiction of a team’s defensive output. The Hokies ranked third in fewest methodical drives allowed.

The Hokies lose 29.1 percent of their defensive snaps from a season ago, which is enough to indicate that things will, in fact, be different defensively in 2015, but return two of the top corners in the Atlantic Coast Conference in Kendall Fuller and Brandon Facyson. That tandem has the ability to take away opposing wide receivers; in the case of Ohio State, that’d be Michael Thomas, a potential first-round NFL draft pick in 2016, and James Clark.

While Virginia Tech hardly had potent offensive schemes last season, they return Michael Brewer at quarterback, and have some playmakers for him to target on the outside. Furthermore, the team has the luxury of hosting Ohio State in a season opener, where mistakes are most likely to happen.

Michigan State

The Spartans have split their last four meetings with Ohio State and last won in the Horseshoe in 2011, when Meyer wasn’t the coach in Columbus. Michigan State and Ohio State meet late in the season and appear primed for a marquee matchup to decide the Big Ten East.

Losing senior linebacker Ed Davis is a big blow to a Michigan State squad that was looking to produce yet another formidable defensive presence in 2015.

However, quarterback Connor Cook is among the most experienced quarterbacks in college football this season with an acumen that only improves late in games. He’ll also be playing behind one of the sturdiest veteran offensive lines in the nation. As a whole, Michigan State has ranked in the top 10 in turnover margin each of the past two seasons, while Ohio State hasn’t eclipsed the top 30.

The Spartans’ passing attack ranked No. 36 in the country last season in yards per game (265.6), but had a top 25 team quarterback rating (148.5). Michigan State isn’t an air-raid offense; it has a balanced offensive approach that has been shown to be fruitful against Ohio State defenses recently.

Mark Dantonio loses 32.9 percent of the team’s defensive snaps from a season ago, but has led a top 12 scoring defense in each of the past four seasons. There’s also this: Michigan State led the country in fewest methodical drives allowed in 2014.

TCU

In their first season as co-offensive coordinators, Sonny Cumbie and Doug Meachem took the Horned Frogs from No. 89 in scoring to No. 2, averaging 46.5 points per game. Over the final two games of the 2014 season—an annihilation of Iowa State and Ole Miss—Gary Patterson’s crew racked up 1,145 total yards and won by a combined score of 97-6.

Captained by quarterback Trevone Boykin, who is pegged as the Heisman front-runner, the team returns all of its offensive firepower, including wide receiver Josh Doctson (school-record 1,018 receiving yards, 11 touchdown catches), and running back Aaron Green (second-team All-Big 12).

Patterson loses just 17.5 percent of the team’s offensive snaps from last season, but loses 48.3 percent of defensive snaps—a mind-bending portion.

The biggest question mark for TCU is clearly the defensive side of the ball, particularly if this year’s squad can play anywhere in the general vicinity of last season’s group, which ranked fourth in the country in opponent-adjusted defensive efficiency. Under then-defensive coordinator Dick Bumpas, the Horned Frogs had a top 25 defense in scoring and stopping methodical drives. However, TCU hasn’t ranked lower than 11th in DFEI since 2011 and Patterson-run teams have led the country in total defense four times, suggesting that the defense will surely rebound with new cogs.

Although the Buckeyes had little difficulty dispatching the Ducks, a team with an oft-discussed high-intensity offense, the Horned Frogs are ostensibly destined to shatter offensive records this season. If new co-defensive coordinators Chad Glasgow and DeMontie Cross can instill a similar pedigree this season, the Horned Frogs are as dangerous as any team and the Buckeyes, even with the exorbitant talent they have on the defensive side of the ball, might not be able to stop the high-octane offense. A team from the Southeastern or Pacific 12 conferences could be on this list, but the blood-bath schedules for the top teams in those respective conferences make TCU a more likely team to square off against Ohio State this season, per Vegas Insider.

Currently, the Buckeyes are scheduled to play just one ranked opponent in 2015: Michigan State, at home. Only four times since 2000 has a team qualified for back-to-back appearances in the national championship game and only twice has a preseason No. 1 team gone wire to wire as the top team in America. Ohio State certainly could do it, but the aforementioned teams have the talent to end their dream.

Josh Planos has been published at the Wall Street Journal, the Atlantic, the Guardian, the Pacific Standard and VICE, among other publications. He has been heard on CBS Sports Radio, Fox Sports Radio and ESPN Radio. Planos is currently a Digital Editor at KETV NewsWatch 7 and a freelance writer.