When center John Estes went down with an injury during practice the other day, Hawai'i head football coach Greg McMackin acknowledged his heart skipped a beat ... or three.

For one thing, the Western Athletic Conference's most accomplished offensive lineman might be the player the Warriors can least afford to lose among the 100-plus on hand.

For another, the Warriors have endeavored to tread an especially fine line this year between getting their frontline players more collision-ready for the start of the season and not unduly banging them up in the process.

So far — and fingers remain tightly crossed in the waning days to the Sept. 4 opener — they would seem to be on the way to striking that most elusive of balances.

Entering tonight's first under-the-lights workout at Aloha Stadium, Estes is expected back soon from what has been listed as a shin bruise and medical staff say there have been "just the normal volume" of strains and sprains with few serious injuries.

This is the 100th anniversary of the beginning of football at UH and the philosophical tug-o-war over how much hitting is enough has probably been waged many of those seasons. One school of thought, embraced by Dick Tomey while he was at UH, held that the more a team hits in preseason practice the more game-ready it will be. But sometimes UH was its own worst enemy in injury-plagued starts, too.

On the flip side, the June Jones-held pro theory says it is wiser to save the wear and tear for the season, even if the crispness of tackling and blocking sometimes suffer in the beginning.

Attempting to plow the middle ground is McMackin, who has worked with both men and styles, coming to recognize the merits — and potential pitfalls — of each. "You don't ever want to lose anybody (in preseason), but I don't want to sugarcoat it, either," McMackin said.

Two years ago in the WAC opener at Louisiana Tech, a game that just about KO'd the Warriors' BCS hopes before they took flight, UH's rusty tackling forced then-defensive coordinator McMackin to call wholesale run blitzes to slow the Bulldogs in a game UH had to go to overtime to pull out, 45-44

With a rebuilding defense in 2009, the Warriors know they are going to have to prove they can control opponents' ground games. Moreover, as UH seeks to upgrade its own running game, building timing is a necessity. But having too many of their top players on the sidelines does the Warriors no good, either.

Ironically for such a physical sport, finding a delicate balance can be crucial. Showing no indication of an intentional pun, McMackin observes, "How much — and how — you hit can be a touchy situation."