NEW YORK — On a day when contending major league baseball teams traditionally add significant pieces to their rosters, the New York Yankees not only did not add anyone, but they may well have lost a player they were relying on to play an important role for them down the stretch.

Just minutes before Tuesday’s 4 p.m. nonwaiver trade deadline, Yankees general manager Brian Cashman learned that J.A. Happ was showing symptoms of coxsackievirus, a highly contagious disease commonly known as hand, foot and mouth disease. The left-handed starter was just acquired in a trade with the Toronto Blue Jays on Thursday.

“How about that?” Cashman said before Tuesday night’s game against the Baltimore Orioles, which the Yankees won, 6-3, at Yankee Stadium. Masahiro Tanaka (9-2) pitched six shutout innings, and Miguel Andujar hit a three-run home run, his 13th of the season, in the fifth inning of a mostly drama-free game against an Orioles team with the worst record (32-75) in baseball.

For the Yankees, the day’s drama occurred about three hours before first pitch, when Cashman was told about Happ’s illness.

“I got a call from our trainer,” Cashman said. “He said, ‘I’m not sure what’s going on here, but J.A. Happ has some complaints, he’s not feeling right, and he had noticed some blistering.'”

Cashman said Happ was sent to NewYork-Presbyterian Hospital, where he received an official diagnosis of a mild case of the disease. “So we sent him home.”

Happ pitched well in beating the Kansas City Royals in his Yankees debut on Sunday and may make his next start against the Boston Red Sox at Fenway Park on Saturday.

“There’s no real treatment. You just monitor the patient and let the virus take its course,” Cashman said. “He’s still scheduled to start. That’s not something that as of now is in jeopardy as of yet. The diagnosis is a very mild case, and our internist felt if everything is as-is right now, he probably would be able to go on Saturday. But it’s a to-be-determined story.”

Cashman said right-hander Luis Cessa would be pulled from his start for the Class AAA Scranton/Wilkes-Barre RailRiders after one inning Thursday night in case he is needed to replace Happ.

Right-hander Lance Lynn, acquired in a trade with the Minnesota Twins on Monday and expected to arrive in New York on Tuesday night, was also an option, Cashman said.

“We’re in a fluid situation,” he said. “Interesting trade deadline press conference, right?”

Before the announcement of Happ’s illness, it appeared the Yankees’ 2018 trade deadline would be a no-news-is-good-news kind of day.

The Yankees believed they were done trading for the time being, even without acquiring an outfielder to fill the void left when Aaron Judge went on the disabled list with a wrist fracture Thursday. They had acquired Happ to shore up their rotation and Lynn to add a long reliever to their bullpen in the wake of the Monday night trade of Adam Warren to the Seattle Mariners in exchange for international signing bonus pool money.

Asked if he was disappointed that the Yankees had not made a “big splash” at the deadline, Cashman said: “It doesn’t have to be splashy. It just has to work.”

Manager Aaron Boone called the team’s trade deadline moves “strong.”

“I feel like Cash and the front office went out and got us some significant pieces to finish off our club and put us in a position to finish off what has been the start of a really good season for us,” Boone said. “We’re excited about the moves we’ve made. We think we’re a better club.”

Happ’s performance on Sunday, in which he allowed the Royals one run and three hits over the first six innings of a 6-3 Yankees victory, appeared to cement his spot in a rotation that, aside from Luis Severino and Tanaka, has been shaky for much of the season. And with Severino struggling recently, the acquisition of Happ took on greater importance.

But now, with Happ’s status uncertain, Lynn, a former All-Star who won 18 games for the St. Louis Cardinals in 2012, may assume a more prominent role. The Yankees originally intended to have him take on Warren’s role in their bullpen while making an occasional spot start. Beginning with Tuesday’s game, the Yankees face a stretch of 20 consecutive games as well as a makeup doubleheader against the Orioles in Baltimore on Aug. 25.

“We had to determine if we could import someone who could be available in the event we needed more starting pitching, plug and play, or pitch out of the pen with more length,” Cashman said. “Lance Lynn checks those boxes.”

But as for adding an outfielder to replace the injured Judge, Cashman said the Yankees were unable to find the proper fit. Judge is expected to be out until late August with a chip fracture of the right wrist after being hit by a pitch in the first inning of Thursday’s 7-2 victory over the Royals. Among the names mentioned to replace him were Curtis Granderson, a Yankee for four seasons, and Andrew McCutchen, a former winner of the National League Most Valuable Player Award.

“We kicked the tires in a lot of different things, but we were not able to match up in a comfortable way,” Cashman said. “Right now, things stay as they are.”

This article originally appeared in The New York Times.

Wallace Matthews © 2018 The New York Times