Virginia Tech defensive coordinator Bud Foster is only facing one team on Sunday, but he's had to prepare for four offenses. 

Life gets complicated when you're trying to stop a transfer quarterback with a new offensive coordinator.

"These first few games," Foster told Sports on Earth, "there's a lot of question marks." 

Of course, some teams have more question marks than others. The Hokies will play ex-rival West Virginia for the Black Diamond Trophy at FedEx Field in suburban Washington, D.C., on Sunday, and the Mountaineers will suit up Florida transfer Will Grier in his WVU debut.

So, naturally, Foster and his Hokies defensive staff dug up the film from his six-game, undefeated run with the Gators in 2015. 

"With that, you're mostly just trying to assess his skill set," Foster said. 

The Hokies examined film from West Virginia head coach Dana Holgorsen's offense last year, but Foster had to spend time diagnosing tape on Holgorsen's new play-caller, Jake Spavital. A Holgorsen protégé, Spavital went on to call plays at Texas A&M and coordinated the California offense last year before landing with his old boss in Morgantown after Sonny Dykes was fired in Berkeley. 

If you're keeping score, that's the 2016 West Virginia and Cal offenses, Florida's offense in 2015 and the brief snippet Foster got to see in the Mountaineers' spring game in April, when Grier completed 12 of 18 passes for 202 yards. 

"Like everybody else's spring game, they're not going to show much, but you get a chance to evaluate personnel," Foster said. "We're looking at the similarities in both schemes, but the subtle differences in Jake's schemes he's used in the past and what he'll use against us." 

It's complicated, but Foster is far from alone, especially as a small army of transfer quarterbacks prepare to make their debuts this weekend. 

Florida announced Wednesday that redshirt freshman Feleipe Franks will start Saturday's game, but there's still a chance Jim Harbaugh and Michigan could see Notre Dame graduate transfer Malik Zaire at some point. Chris Petersen and 2016 playoff participant Washington will try to slow down Louisville transfer Kyle Bolin, who's making his debut for Rutgers. Justin Wilcox will make his debut as head coach of California against North Carolina, who'll likely play LSU transfer Brandon Harris at some point, even if he doesn't start. 

It can get confusing. 

"You go on information that you know and you've seen and you try to anticipate," Harbaugh said. "There's no exact tape to look at or to have an understanding, so you're trying to predict and anticipate and build your game plan around that knowing there will have to be 'INAs.' You'll have to improvise and adjust as the game unfolds." 

Every coach in this type of situation is playing a guessing game. And though each wants to make an educated guess, getting too educated can be a problem. You have months to prepare, but digging too deep down the rabbit hole is counterproductive. 

"We watch as much tape as possible, but we try not to have our kids chasing ghosts," Petersen said. "We study what we can, but it always comes back to us doing our job. Trust your rules and play fast." 

One of coaching's most consistent tropes is that nervousness is what happens when you're not prepared. But in situations like these, there's no way to fully prepare, no way to fully account for all the possible variables that can present themselves come game day. It can be maddening for coaches, but it's unavoidable, despite them doing everything possible to quiet that churning in their stomach as kickoff creeps closer. 

The process is the same for most. Collect and watch tape of the quarterback in his previous scheme and try to watch for tendencies while eyeballing assets like arm strength, mobility and vision. Then, try to pounce on weaknesses like skittish feet in the pocket or a propensity to make mistakes under pressure. Then, get a feel for what the concepts in the current scheme will try to accomplish and guess how the play-caller will try to emphasize his new passer's strengths while hiding his weaknesses. 

"The dynamics are different every year," Wilcox said. "You don't want to start chasing ghosts." 

In Foster's case, at least three of the four offenses he's studied up on are close cousins in Mike Leach's Air Raid coaching tree. 

"They're similar in a lot of ways. You see a lot of the same concepts. You do see with Spav, a little more quick game then maybe West Virginia last year," Foster said. "Cal's quarterback [Davis Webb] was drafted high, but they also threw a lot of quick game, a lot of bubble, quick hit and throws and then take a shot or a double move off those quick-hitting throws. WVU was the same, but their quarterback was a little different guy than what Cal had." 

This weekend, the veil will be lifted, the guesses proven right or wrong. If it's the latter, adjustments will decide whether confused defenses can still salvage a win.