Reliever Thompson is first acquisition to join Nats

The first of the 12 prospects the Nationals acquired before this week's trade deadline has joined the active roster.

Mason Thompson, a reliever the Nats received from the Padres for Daniel Hudson late Thursday night, has arrived in Washington and was formally placed on the 26-man roster for tonight's game against the Cubs.

The 23-year-old right-hander does have some big league experience, having debuted for San Diego last month. In four appearances, he allowed one run on four hits and one walk over three innings, striking out two.

A physical presence at 6-foot-7, 223 pounds, Thompson battled injuries early in his minor league career but began to take off last season after becoming a full-time reliever. His 5.74 ERA in 23 games at Triple-A El Paso may raise eyebrows, but his 1.238 WHIP and 24-to-8 strikeout-to-walk ratio are probably more reflective of his performance in a notoriously hitter-friendly league.

"Big arm, big kid," manager Davey Martinez said in his pregame Zoom session with reporters. "I'm looking forward to watching him pitch."

Rated the Nationals' 16th-best prospect by MLBPipeline.com once the dust settled from this week's trade deadline frenzy, Thompson's debut won't carry the importance of the upcoming arrivals of catcher Keibert Ruiz and right-hander Josiah Gray. But as they transition into rebuilding mode, the Nats plan to use the next two months to evaluate as many of their newcomers as possible in person, not just on video or via minor league reports.

"I want to see these guys," Martinez said. "I know he's pitched well in (Triple-A), but I want to see him here. I want to see him pitching for us and get him used to some of the things we do. We're going to get these guys and they're going to play. He's going to come out here and pitch. We're going to put him in a game and see how he reacts and how he does."

Thompson is the first of 12 new additions to join the roster in Washington, but a couple more may be here very soon. Ruiz and Gray, in particular, appear to be on the verge of being added, with Gray a strong candidate to pitch in the big league rotation within the next week.

The Nationals have named Erick Fedde as Sunday's starter against the Cubs, but Patrick Corbin won't be ready to pitch again on normal rest until Tuesday. That leaves Monday's game against the Phillies up in the air, and Gray would seem to be strong option to take the spot.

Asked if he knows his upcoming rotation plan, Martinez laughed and replied: "I do not," before adding: "We are trying to figure out a lot of things right now."