Clint Dempsey

Clint Dempsey, celebrating after he scored against Ghana, could move from an attacking midfield position to forward in place of injured Jozy Altidore against Portugal in a World Cup Group G game on Sunday. (Michael Steele / Getty Images / June 16, 2014)

The U.S. will extend no pity to Portugal in today's anticipated World Cup match. Although their opponent has more lineup holes to patch, the Americans have no obvious or reassuring solution to their single required change.

As a striker, Jozy Altidore is one of a kind on the U.S. roster. There is no understudy to plug in for Altidore, whose hamstring injury has shelved him for this match -- and, in all likelihood, others.

Coach Juergen Klinsmann could tap a forward, Aron Johannsson or Chris Wondolowski, to fill in. All the inexperienced Johannsson did against Ghana was make U.S. supporters appreciate Altidore more. Wondolowski led, by himself or with another player, Major League Soccer in goals for three consecutive years but has tailed off.

So there is growing speculation that Klinsmann will audible from the preferred 4-4-2 formation to a 4-5-1, with five midfielders and Clint Dempsey operating solo in the front.

Portugal, with a decimated defense and a disadvantageous goals difference, figures to push forward even more than usual. An extra U.S. mid could clog up the center of the field and gum up the Portuguese attack, at least on paper.

Another concern is Dempsey's breathing. He will carry on with a broken nose from the Ghana game -- and apparently without a protective mask. In the projected high humidity, the usually indefatigable Dempsey could get winded.

Forget about sympathy for the other side. The U.S. is holding its collective breath about its own lineup.