Wigan Athletic will arrive in west Yorkshire today fortified by an infusion of Vitamin D but Huddersfield Town have been galvanised by the appointment of a new manager.
While Roberto Martinez's players were busy absorbing as much sunshine as possible in Tenerife last week, their FA Cup fifth-round opponents won a fourth-round replay at Leicester City before welcoming Mark Robins into the office vacated by Simon Grayson.
Martinez trusts Wigan's less stressful build-up will propel his team into the quarter-finals for only the second time in their history. "A change of environment always helps," he says. "And the Vitamin D from the sun is very important."
Regardless of respective Vitamin D levels, both he and Robins face similar dilemmas. With their teams in danger of dropping out of the Premier League and the Championship respectively, do they prioritise league over Cup? Is Wigan's relegation six-pointer at Reading on Saturday all-important? Should Robins concentrate on Tuesday's second-tier trip to Nottingham Forest?
Martinez invariably rotates his team for the Cup. "We've been able to use the FA Cup to give a lot of good playing time for youngsters," says Wigan's manager.
"It means Sunday will be a welcome distraction from the league but I don't see one game as being more important than the other. I look at every game we have left and say they're all vital, that they must all be treated like cup finals. And today is a glorious opportunity for Wigan to reach the quarter-finals for only the second time."
Robins, who left Coventry to become Huddersfield's fifth manager in as many years, has a bit of history in this competition, having almost certainly saved Alex Ferguson's job at Manchester United by scoring a vital FA Cup third-round winning goal at Nottingham Forest in 1990. United went on to win the trophy and again had Robins to thank for another winner in a semi-final replay against Oldham.
Robins has a place in Manchester United folklore thanks to that goal against Forest, even if Ferguson, though, does not believe defeat would have cost him his job.
"The goal at Forest was an important goal, don't get me wrong, and who's to say what would have happened without it, but I don't think it saved my job.''
Now 43, the former striker has won many admirers through some impressive work on limited budgets at Rotherham, Barnsley and Coventry and aims to revive the fortunes of a club which won the League three times during the 1920s and lifted the FA Cup in 1922. It is a situation Robins never anticipated.
"I've already been knocked out of the FA Cup once this season at Tottenham with Coventry," he jokes.
"Roberto Martinez's teams always play good football so this is a game to look forward to and an opportunity to pit our wits against Premier League opposition."
Martinez may be additionally spurred after pictures of Wigan's players lying beside their hotel pool in Tenerife were posted on Twitter and attracted barbs from cynical fans.
"I understand that certain pictures can send the wrong message, but the players were very professional," says the Spaniard.
"It was very good for the group dynamics and we worked a lot more than we would have done here because of the weather. The players apologise if there was any wrong message sent.
"They have some time to rest, as you would imagine, and if you can do that with a bit of sun, it really helps the bodies."
Huddersfield Town v Wigan Athletic,