MIAMI (AP) — Team USA manager Davey Johnson was right to have reservations about playing Adam Dunn at first base.

The desperation defensive deployment backfired Wednesday night in the World Baseball Classic when Dunn made a wild throw that led to four unearned runs, and Venezuela won Group 2 by beating the Americans 10-6 to conclude second-round play in Miami.

Both teams had already qualified for the semifinals this weekend in Los Angeles. Injury-plagued Team USA is expected to make several roster moves before then.

First baseman and cleanup hitter Kevin Youkilis was ruled out for the rest of the tournament Wednesday because of mild ankle and foot injuries. The only first baseman on the list of potential roster replacements — Derrek Lee of the Chicago Cubs — has been hampered by a sore thigh.

‘‘We really don’t have a first baseman to go to, and that creates a problem,’’ Johnson said. ‘‘There are not really any good options.’’

Four other Americans have been sidelined by injuries since the start of round two, and there was concern in the U.S. dugout when third baseman David Wright fouled a ball off his foot in the first inning.

Wright cracked his left big toenail and hobbled through the rest of the game, in part because the only available position player on the bench was catcher Brian McCann. X-rays were negative, and Wright said he’s certain he’ll be able to play in the semifinals.

‘‘We’ve got to stop getting hurt,’’ Wright said with a smile, referring to the wave of injuries. ‘‘A lot of this from what I see is stuff that, if it’s in the middle of the season, you can play through. But obviously the teams want to take every precautionary measure to make sure you’re ready to go the first week in April.’’

The WBC semifinals begin Saturday, when Venezuela will play the second-seeded team from Group 1 at Dodger Stadium. The Americans play in the other semifinal Sunday.

‘‘I can’t wait,’’ Wright said. ‘‘Making it to the final four has been our goal.’’

The semifinalists from Group 1 in San Diego will be South Korea and the winner of Wednesday night’s game between Cuba and Japan.

The Americans qualified for the semifinals for the first time by scoring three runs in the ninth inning Tuesday night to beat Puerto Rico 6-5, but they failed to come up with much of an encore.

‘‘After Tuesday night, anything was going to be a letdown,’’ left fielder Mark DeRosa said. ‘‘That was one of the great moments in a lot of guys’ careers.’’