Tim Wakefield, left, shows Red Sox pitcher Daisuke Matsuzaka how to throw a knuckleball before their game yesterday.

AP / Brita Meng Outzen

FORT MYERS, Fla. — After declining to answer questions after his outing Monday in Sarasota, Daisuke Matsuzaka told Japanese reporters yesterday that his lack of control (five walks in five innings) was the result of poor focus on his part.

“The problem was not mechanics,” Matsuzaka said. “It was mental. I couldn’t concentrate at all. If it had been a regular-season game, I could have forced myself to concentrate. But this time of year ... .”

Matsuzaka, who held the Reds hitless over five scoreless innings, took some consolation in the fact that “even in that situation, I could keep my team in the game. It became a good exercise.”

Both manager Terry Francona and pitching coach John Farrell have said that Matsuzaka can be too demanding of himself, and that was evident again yesterday when he expressed regret over Monday’s outing.

Mastsuzaka didn’t directly address why he chose not to speak with reporters Monday.

Wakefield ready to go

The Red Sox fell to the Pittsburgh Pirates, 3-2, yesterday.

Tim Wakefield allowed a two-run homer to Pirates catcher Ronny Paulino and another solo run in the second on consecutive doubles by Luis Matos and Andrew McCutchen before settling down to throw four shutout innings.

The Sox got a run from an alert Julio Lugo, who scored from third on a wild pitch that didn’t get more than six feet from Paulino. A run-scoring single from David Ortiz in the fifth accounted for the final run.

“I’ve built my pitch count,” said Wakefield, who will pitch in an intra-squad game in minor-league camp Sunday. “I’m ready to get the season started.”

Brendan Donnelly, J.C. Romero and Joel Pineiro each contributed a scoreless inning to finish the game.

Castillo traded to O’s

The Sox dealt veteran catcher Alberto Castillo to the Baltimore Orioles yesterday in exchange for left-handed-hitting outfielder Cory Keylor.

Keylor, 27, was the Orioles’ 2006 Minor League Player of the Year last year at Double-A Bowie where he hit .294 with 10 homers and 68 RBI in 124 games.

Keylor was assigned to minor-league camp.

The Sox also returned non-roster invitee Kevin Cash, a catcher, to minor-league camp.

Jon Lester, just three months removed from cancer treatment to battle non-Hodgkin lymphoma, will begin the season at Single-A Greenville, where he will make three to four starts before being reevaluated in late April.

“He’s chomping at the bit,” said Francona. “But I think he understands.”

Around the bases

Manny Ramirez remained out of the lineup with a virus, which struck him Sunday night. He’s expected back in the lineup tonight against the Twins. ... Curt Schilling makes his final start of the spring this evening, but will be scaled back in terms of pitch count in anticipation of Monday’s regular-season opener. ... The Sox will take a look at Clay Buchholz in tomorrow’s spring finale against Tampa Bay. Buchholz, who was recently ranked as the organization’s third-best prospect, will likely open the season at Class-A Lancaster. ... Mike Timlin (strained oblique) threw a 35-to-40 pitch bullpen session yesterday morning, his first time off the mound in almost two weeks after a mid-March setback. He’ll repeat the session tomorrow and may get into a minor-league game Saturday.

smcadam@projo.com