Varitek is an agent of change for Matsuzaka

BOSTON -- After watching Daisuke Matsuzaka struggle through a late-summer stretch in which he lost four of five starts, catcher Jason Varitek called the pitcher aside and not so delicately suggested the rookie stop relying so heavily on his fastball and begin mixing speeds a little more.

Despite the language barrier, Varitek’s message got through loud and clear. As a result Matsuzaka heads into tonight’s start against the Angels in Game 2 of the American League division series coming off arguably his best start of the second half, holding the Minnesota Twins to two runs in eight innings of a 5-2 victory last Friday that clinched the AL East title for Boston. He got a career-high 12 groundball outs and struck out eight, the most he’s had in a game in nearly two months.

“I keep stressing and reiterating that it’s all about execution,” Varitek said Thursday following Boston’s brief morning workout. “And in his last two starts he’s executed.”

In warmups before the Twins game last weekend Matsuzaka even tried fine-tuning a split-finger fastball, a pitch Varitek said Matsuzaka never worked on in the bullpen yet often tried to throw in games.

“We’ve all seen the bumps in the road, the hiccups in some of the outings,” Manager Terry Francona said. “But being intimidated or shrinking from a challenge won’t be one of them. I think this stage will be a good place for him to show what he can do.”

The Red Sox bullpen has had four days off this week, thanks to three scheduled off days and Josh Beckett’s shutout in Game 1. But closer Jonathan Papelbon doesn’t see that as a problem.

“Nah. We stay sharp,” said Papelbon, who hasn’t pitched since Sunday after appearing in 59 regular-season games.

The Boston bullpen was the best in the league with a 3.10 earned-run average, but the extended rest could leave their relievers, who are accustomed to working several times a week, too fresh.

Neither of Boston’s setup men, Eric Gagne or Hideki Okajima, has pitched more than two innings since Sept. 25.

“We hope that when you get into a situation where you need a pivotal out from your bullpen that they’ll be rested, not rusty,” Francona said.

When the Red Sox entered the clubhouse after their Game 1 win, they found gray T-shirts with the words “Do It. . .” on the front and “For the Guy Next to You” across the back.

“I don’t know where they came from,” center fielder Coco Crisp said while examining the label inside his shirt. But he quickly fingered David Ortiz.

“It says ‘Beefy’ on it,” Crisp said. “Maybe they’re from Big Papi. Papi’s the beefiest one here.”

kevin.baxter@latimes.com