When Greg Gibson was announced as the home-plate umpire Tuesday night, there was a smattering of boos from the still-arriving crowd at Citizens Bank Park.

Before the game began, Gibson again declined the chance to explain his reasoning behind a disputed call in Monday's 3-2 Phillies loss.

"I can't talk," Gibson said, insisting only Frank Robinson, baseball's senior vice president of major-league operations, could speak.

Following Monday's game, Gibson did not comment either. "Per MLB policy, we're not allowed to talk," crew chief Sam Holbrook said then.

But there is no Major League Baseball policy that restricts umpires from speaking to reporters to explain a controversial call. In fact, it is common practice for umpires to do so - i.e. Jim Joyce after the imperfect game in Detroit, or Bob Davidson following a Phillies-Marlins game earlier this month.

"We are addressing it," a spokesman from the commissioner's office said Tuesday.

It's possible officials will tell the umpiring crew they must honor requests for comment in the future.

Regardless, there was still confusion over the call in the eighth inning of Monday's game, when Michael Bourn bunted a ball up the first-base line and appeared to run out of the baseline to avoid Ryan Howard's tag.

Rule 7.08 (1)(a) says the runner's baseline is established when the tag attempt is made. He may not exceed three feet away from that imaginary line. Gibson told Charlie Manuel that Bourn had not exceeded that limit.

Manuel said he would have liked to hear a further explanation from the umpiring crew following the game.

"I think in your position that you should be accountable," Manuel said. "But I don't have anything to do with the umpires. Actually, I don't like calling out an umpire. I definitely don't want to do that because I know that that's a hard job. I don't know what to say about that."

Manuel said he wasn't trying to get thrown out of the game when he ran onto the field. Eventually, it became his goal.

"When he started going to rush me off the field," Manuel said, "I was going to leave on my terms."

Werth distracted

So there is an explanation. Sort of.

Video replays of Monday's game clearly show Houston pitcher Brett Myers sticking out his tongue at Jayson Werth before he threw his fourth intentional ball to Carlos Ruiz. Then, of course, Astros catcher Humberto Quintero picked Werth off second base in a truly bizarre play.

"I was screened by Myers," Werth said.

When Quintero threw the ball, Ruiz was blocking him. And Werth's view was obscured by Myers. He didn't see the ball until it was at the pitcher's mound. By that point, he didn't have enough time to get back to the bag.

Werth said he was upset because he's normally the one trying to throw behind players and catch them napping off the bag.

"The thing that took me off most about it was I'm always trying to get guys doing that," Werth said. "And I end up getting caught."

Manuel was clearly not thrilled with the play after the game Monday night. He was in a more forgiving mood Tuesday.

"You're going to make mistakes," Manuel said. "That's going to happen. But we're going to play the game the right way. I've seen that in the minor leagues a few teams. I've seen it. I could tell when the play developed that Myers opened up a lane for him. He was going to throw to second because the guy definitely stayed there to cover."

Extra bases

J.A. Happ starts against his former team Wednesday. He will be opposed by Roy Halladay, who is seeking win No. 17. . . . The Phillies signed lefthander Nate Robertson to a minor-league deal. Robertson, 32, who started 18 games for the Marlins earlier this season, will pitch for triple-A Lehigh Valley on Thursday. Robertson recently opted out of a minor-league deal with St. Louis.

Contact staff writer Matt Gelb at 215-854-2928 or mgelb@phillynews.com. Follow on Twitter @magelb.