The Nats woulnd’t have moved Nate Karns if the Rays hadn’t included Felipe Rivero. (Jonathan Newton / The Washington Post)

As pitchers and catchers officially reported for spring training Thursday morning, the Nationals executed their final requisite roster addition of the offseason, acquiring a tested, viable backup catcher to place behind Wilson Ramos for a young pitcher while also replenishing their farm system.

The Nationals traded right-handed starter Nate Karns to the Tampa Bay Rays for backup catcher Jose Lobaton and two 22-year-old minor leaguers – left-handed starter Felipe Rivero and outfielder Drew Vettleson, both of whom Baseball America ranked among Tampa’s top 20 prospects.

The Nationals sought to acquire a backup for Ramos all winter and eyed Lobaton, 29, as far back as the winter meetings. Lobaton appeared in 96 games last year for the Rays and hit .249/.320/.398 with seven homers. The Nationals coveted him for his ability to switch-hit and his defensive acumen, particularly his ability to frame pitches, which General Manager Mike Rizzo called “a key.” The Nationals will also control Lobaton’s contractual rights through the 2017 season.

“He fit the criteria we’re looking for,” Rizzo said. “Switch hitting is certainly a bonus.  Our statistical analysis people rank all the catchers in baseball, and he ranks very well in the framing.”

Lobaton woke up in his Orlando home at 7 a.m. Thursday morning, unable to sleep. Rumors of a trade had swirled the night before, and he did not know if he would report to the Rays or Nationals for spring training.

“I told my wife, ‘I can’t sleep. I’m thinking too much,’ ” Lobaton said. “ ‘If I’m going to be part of the Nationals or not. I just want to know. I just want to make sure I’m going somewhere.’ ”

Lobaton received a call from the Rays around 10 a.m. with news of the deal. “I feel happy, because it’s a new team, they’ve got faith in me.” But he also had to say goodbye to his teammates from the past four years. Rays ace David Price called him and asked, “What happened?” He spoke with all of the Rays’ starting pitchers.

His closeness with the staff speaks to Lobaton’s priority. He views helping his pitching staff as his primary mission, ahead of his offensive production.

“I’m the kind of catcher, I like to talk to the pitcher,” Lobaton said. “Whatever they want. I’m not the kind of catcher who is like, ‘I want something, I’m going to call it.’ I want to do whatever they want. He’s got the ball. I’m not the kind of guy who is going to force what pitch I want. It’s not like that. Communication, we worked a lot with the Rays on that. ‘Just let me know’ – that’s all I say to the pitchers. Whatever you want, I’m going to do my best.”

Lobaton arrived at Space Coast Stadium just before 1 p.m. and immediately sat next to Ramos. Ramos, incidentally, played with Lobaton in Venezuela, the home country of both players, in the winter of 2010.

“Good guy, good teammate,” Ramos said. “Hopefully, he will help the team. That’s what we want. He’s good. He hits well both sides of the plate. He’s got good defense, a good arm. He can call the games. He’s a good catcher, man.”

Lobaton planned to lean on Ramos to learn the Nationals’ rotation, which he called “unbelievable.”

“It made me feel better that the team has faith in me, that you can handle those guys,” Lobaton said. “It’s a long spring training, and we’ve got time to get ready and be in that place that I want to be with them.”

Karns reported to Space Coast Stadium aware of trade rumors involving his name. His agent notified him while he ate dinner Wednesday night. His mother called and asked him, “Is it true?” He replied, “I have no idea.”

In 2013, Karns made his debut with the Nationals, the team that drafted him in the 12th round in 2009. He endured major shoulder surgery before the Nationals named their 2012 minor league pitcher of the year. In three big league starts, he allowed 10 earned runs in 12 innings, including five homers. He was eager to compete for the Nationals’ fifth starter spot.

And then, before 10 a.m., Rizzo pulled Karns into an office and told him he had been traded. Karns had “no hard feelings.” He stuffed his belongings into a big, black garbage bag. Across the room, Sandy Leon and Jhonaton Solano, the two young catchers who planned to compete to backup Ramos, wore long faces as they showed each other their phones.

“Like I said to Karns when I talked to him today, we’re really proud of Karns,” Rizzo said. “This was a 12th-round pick that had pretty major shoulder surgery and grinded through and battled back. A really good, young, upside pitcher that pitched in the big leagues for us. He’s got a good mental makeup. He’s a pitcher that’s going to help Tampa Bay and was a guy that in our plans.”

The Nationals, Rizzo said, would not have made the trade if Tampa had not included Rivero and Vettleson. Rizzo was especially bullish about Rivero, a 22-year-old who last season posted a 3.40 ERA in 25 games (23 starts) at Class High-A. Rizzo considered him a replacement for Robbie Ray, whom the Nationals traded to Detroit as part of the package that landed Doug Fister. Baseball America ranked him the Rays’ No. 17 prospect.  “A huge-upside left-handed starter,” Rizzo called him.

The Rays chose Vettleson with the 42nd overall pick in 2010. Last year at High A, Vettleson hit .274/.331/.388 with four homers. Baseball America rated him the No. 20 overall Rays prospect.

One American League scout called the Lobaton-Karns piece of the deal “even.” He saw Karns as a power arm who profiles eventually as a reliever and Lobaton as an experienced, switch-hitting catcher who will provide the Nationals what they need behind Wilson Ramos.

Lobaton looked forward to meeting his new teammates, with an assist from Ramos.

“I don’t know nobody,” Lobaton said. “Now it’s time to make new friends.”