As the Washington Nationals were about to play their final exhibition game on Tuesday afternoon, Manager Davey Johnson still had not informed John Lannan that the two-time Opening Day starter was being optioned to AAA Syracuse.

It was a conversation Johnson was dreading, yet he knew it had to be him to reveal the decision to the veteran left-hander whom Johnson had named the fifth starter earlier in spring training.

So the first inning went by, and then the second, until finally at some point in the third inning of the 8-7 loss to Boston, Johnson broke the news to Lannan in the dugout at Nationals Park.

“Actually I was going to have it before the game, and I then I said, ‘No, no,’” Johnson said. “I kind of put it off, put it off, and I was going to have it right before the game, and I said, ‘I’ll do it during the game.’

“Very difficult decision. A tough one. I respect and like John Lannan a lot. It was a tough day and not the way I like to end up spring training.”

Johnson did not disclose Lannan’s full reaction, and Lannan was not in the clubhouse following the game to address the unexpected move that means Ross Detwiler will be the No. 5 starter until Chien-Ming Wang is back later this month.

But teammates clearly felt for Lannan, who last season won 10 games, posted an ERA of 3.70 and was a steady presence in the clubhouse.

“It’s unfortunate that John has to suffer from that, but that’s the nature of the game,” said pitcher Craig Stammen, who was among the final players to make the opening day roster. “Unfortunately baseball isn’t always as fun as it was when we were kids, and there’s a business part of it at this level. That’s the tough part about today.”

Leadoff hitter Ian Desmond has spent many innings backing Lannan at shortstop, and after he was thrown out at home to end today’s game, he too expressed support on one of the more difficult days of spring training.

The move to send down Lannan, though, does speak to the depth of the Nationals staff and to the confidence the front office has in Detwiler, whose last spring training start included five innings, three hits and one run with five strikeouts. Detwiler pitched one inning today, striking out one and allowing no hits or runs.

Detwiler also is a first-round pick who possesses a fastball in the mid-90s.

“Obviously I’m rooting for Johnny,” said Desmond, who homered and walked twice against the Red Sox. “But it’s a business, and I know that John’s going to persevere and end up okay in this situation regardless.

“It takes a lot more than 25 guys to win a championship, and at some point during the season we’re going to need him, and I know he’s going to be ready. He’s going to go down [to the minors] and keep on working, and this isn’t going to faze him one bit.”