MIAMI -- Trevor Richards showed plenty of promise in his Major League debut, but he also was introduced to the struggles of making it three times through a lineup, especially a postseason-experienced one. The end result was a 7-3 loss to the Red Sox at Marlins Park.
In his first big league start, Richards was victimized in the middle innings, allowing five runs in 4 1/3 frames after he retired the first seven batters he faced on Monday night.
"It's always good to get the first one out of the way," Richards said. "A lot is going on coming up to the debut. It's good to settle in and get into a new groove."

Richards showed good mound presence and command, and he effectively mixed in his changeup. But in the fourth inning, he allowed three two-out runs. A swinging bunt by Xander Bogaerts started the rally. Eduardo Nunez followed with an RBI double off the third-base bag and Christian Vazquez added a two-run double off third baseman Brian Anderson's glove.
"He had some tough breaks," catcher John Holaday said. "Infield hit to Bogaerts, and a ball that hits the bag. If that's a foot away, maybe BA gets to it. If it's the other way, maybe it's a foul ball. That stuff happens. But other than that, he made some good pitches."

In the fifth inning, Hanley Ramirez crushed a two-run homer, and Richards' night ended on Rafael Devers' single after 93 pitches (55 strikes). The 24-year-old right-hander struck out five, walked one and threw 19 changeups, getting five swinging strikes on the pitch.
"I thought he did a great job today," Holaday said. "He made two mistakes, and both of them cost him: the breaking ball to Vazquez, up in the zone a little bit and didn't quite get it out there. And then the breaking ball to Hanley Ramirez."

Earlier on Monday, the Marlins designated right-hander Severino Gonzalez for assignment to make space on the 40-man roster for Richards.
Getting Richards, ranked by MLB Pipeline as Miami's No. 22 prospect, completes Miami's five-man rotation -- at least for now.

With Richards in the fold, the Marlins will go with 13 pitchers and 12 position players. Manager Don Mattingly had a fifth bench player for the first three games, but moving forward, the club plans on having eight relievers and four bench players.
Asked if the roster shuffling may slow down, Mattingly said on Monday afternoon: "Kind of. We still have some things to do, and we still have to make some decisions."
Miami's bullpen is recovering from Friday's 17-inning, 2-1, win over the Cubs, and Saturday's 10-6 loss in 10 innings.
Noteworthy
• J.T. Realmuto (lower back contusion) began catching drills on Monday. It's the first step towards getting him back into game shape. Realmuto will likely need about three weeks before joining the Marlins. Also, Elieser Hernandez (tooth infection), threw 45 pitches in a simulated game on Sunday. Third baseman Martin Prado (left hamstring strain) has been running the bases. Shortstop JT Riddle (right shoulder tendinitis) is progressing with his throwing program, and Dan Straily (right forearm strain) continues with his long toss program.

• Garrett Cooper (right wrist contusion) is getting another couple of days to rest. With an off-day Wednesday before facing the Phillies at Philadelphia on Thursday, the Marlins are hoping they can avoid playing Cooper for a few more games.
"It's still sore," Mattingly said. "We know there is nothing really wrong, other than inflammation. I'd love to be able to not have to use him. It's so hard in the National League not to use guys."
• The plan remains the same for Jarlin Garcia. After he logged six scoreless innings of relief in Friday's 17-inning win over the Cubs, Garcia still projects to be a starter this season. That likely could be in the Minor Leagues, but for now, the lefty remains a bullpen option. The Marlins are monitoring Garcia's innings because he was a reliever last year and threw 53 1/3 innings in 68 MLB games, plus four more innings in the Minors. The Marlins have a 120-130 innings range for Garcia, with rookie southpaw Dillon Peters in a similar range.

• The roof was open on Monday for the fifth straight game at Marlins Park. Mattingly prefers it being open, even though the winds may keep some balls from leaving the park. With the roof closed, the ball carries better.
"I think you know here it's only short term, because of the heat, and the rain, obviously, popping up," Mattingly said. "But I like playing with it open. I know with some guys, you get frustrated if you hit the ball good, and it doesn't go out, but there were some balls that were hit on the other side, too, that didn't go out. I think you have to adjust to your ballpark. If you play in Wrigley and the wind is blowing in, if you hit the ball in the air, you're out."