With a game built around speed, hustle and a knack for finding the open man, Nuggets guard Rudy Fernandez has contributed significantly to Denver’s strong start to the 2011-12 season.

The Nuggets might have to get by without their high-energy sub for a day or two.

Bothered by soreness for the past few weeks, Fernandez left Sunday night’s game against Utah in the second quarter with a strained right Achilles’ tendon. He is listed as day-to-day but does not expect to play when the Nuggets open an extended road trip Tuesday night in Milwaukee.

“It’s feeling better, but every day when I start to run, when I start to jump, it’s bothering me,” Fernandez said Monday. “We’ll see with the treatment what happens.”

Fernandez, averaging 8.5 points and 3.5 assists in 23.8 minutes off the bench, has endured a heavy workload over the past four months.

He helped the Spanish national team defend its title at the European Championships in September and later played 17 games for Real Madrid during the NBA lockout. The Nuggets then survived a schedule that included nine games in 13 days to open the season.

“Right now, it’s coming back a little bit and this is probably the worst feeling,” Fernandez said. “Probably it’s because we have a lot of games in a row. I need a little bit of rest.”

Starting in Milwaukee, the Nuggets play four games in five nights as part of an Eastern Conference road swing. Denver then has three days off before playing at Sacramento on Jan. 25.

“It’s day-by-day,” Fernandez said. “I don’t want to guess (on a possible return.)”

Because he is a high-energy player who relies on quickness at both ends of the court, Fernandez is most effective when he is able to go full-speed. Nuggets coach George Karl pointed to Fernandez’s absence as one of many factors in Sunday’s home loss to Utah.

“The combination of losing Rudy (along with) Andre (Miller) and Ty (Lawson) not having great games brought our playmaking down a little bit,” Karl said. “That’s our engine. Our engine is their decision-making and their ability to find shots for us.”

After watching the film, Karl said the Nuggets also managed only 46 points on 48 shot attempts around the rim. Denver’s 26-of-39 performance at the free-throw line and Paul Millsap’s monster fourth quarter were additional nails in the coffin.

“Don’t overreact. That’s the theory,” Karl said. “We have a good month going, maybe a great month. It’s a crazy year. We need to take what happened, learn from it, and move on.”

The Nuggets are 6-3 this month and 8-5 overall. Six of their final eight games in January are on the road, which should provide an opportunity to bond and grow as a team.

After Milwaukee (4-8), the Nuggets play at Philadelphia (10-3) on Wednesday, at Washington (1-12) on Friday and at New York (6-7) on Saturday.

“All these (next) four games are going to be very important for us,” forward Danilo Gallinari said. “It’s going to be one of the most important weeks of the entire season. We look forward to being focused and trying to get four out of four.”