Joe Mauer knows that the news on Wednesday that his wife, Maddie, is pregnant with twins erupted throughout the Twin Cities.

But he's still walking on clouds himself.

"It's unbelievable,'' Mauer said after the Twins beat Baltimore on Thursday for their fourth straight win. "What a blessing. I'm just very excited. Very happy and really couldn't believe it at first.''

It was hard for the couple to keep the pregnancy a secret, but they wanted to make sure everything was safe before they made an announcement. They knew once a few people found out that word would spread instantly.

There used to be Kodak moments. Now there are Twitter moments. And Wednesday night was a Twitter moment as Mauer began getting congratulatory messages -- and message making sure it wasn't a hoax -- right before he went to bed.

"I really didn't expect what happened [Wednesday] to happen,'' he said.

The babies are due the last week in August, and the Mauers plan to be surprised at what gender they are. Mauer said that he's enjoyed watching his friends and family react to the news, that he plans to ask Jamey Carroll, the father of twins, for plenty of advice and that he's not afraid of changing diapers.

"It's a game-changer,'' he said. "To start off with one is a blessing. To start off with two is an even bigger blessing.''

Mastroianni tweaks a hamstring

Outfielder Darin Mastroianni was 2-for-3 with two doubles on Thursday, but he tweaked his left hamstring during his final at-bat in the fourth inning and was replaced by a pinch runner.

Mastroianni can motor, so any injury to his legs can be concerning. But Mastroianni expected to miss only a day or two. He said the same thing happened during winter ball.

B game

The Twins dropped a 3-0 B game to Boston on Thursday morning before the main game at Hammond Stadium against the Orioles. The B game was to give some younger players some action while helping a few others prepare for the World Baseball Classic.

Aaron Hicks was 1-for-3 with a double. Eddie Rosario was 1-for-3.

Righthander Samuel Deduno gave up three earned runs over 1 2/3 innings. Righthanders Alex Meyer and Jose Berrios were impressive as each threw two shutout innings. B.J. Hermsen gave up a run in the final inning.

On deck

The Twins head to Jupiter to face Mike Redmond and the Florida Marlins. Righthander Vance Worley will start for the Twins, while righthander Henderson Alvarez will start for Florida.