WASHINGTON – In the first inning, Reynaldo López hurled his first four-seam fastball and it felt normal. Then he saw the velocity reading on the board.

“To be honest, I didn’t really know what was happening,” López said through interpreter Franco García. “I feel like that first pitch went out and I thought it was 95 (mph) and I look up and it was 89 (mph), and so that took me by surprise. That was just something I wasn’t expecting.”

After López completed a scoreless bottom of the first inning on Tuesday at Nationals Park, he departed with what the Braves termed as “right shoulder tightness.” After the Braves defeated the Nationals, López said his initial tests – done Tuesday night – came back clean, but added he will get an MRI on Wednesday “out of an abundance of caution.”

“I was definitely relieved when everything came back normal and good, and so I think right now, we’re just being overly cautious,” López said.

Does he think this is a situation that will put him on the injured list?

“No, I think we’re just going to take it day by day and see how everything goes,” he said.

The Braves will know more on Wednesday. Losing López would be a massive blow for a team that is tied for the National League’s third wild-card spot.

On 13 four-seam fastballs on Tuesday, López averaged 91.9 mph – which is 3.6 mph down from his season average. The velocity decrease existed throughout his entire repertoire.

With runners on the corners and two outs in the first inning, Braves manager Brian Snitker, assistant athletic trainer Jeff Stevenson, bullpen coach – and acting pitching coach – Erick Abreu, catcher Sean Murphy and a host of infielders visited López on the mound to check on him. He finished the inning, but the Braves lifted him after that.

“In that first inning, when he got runners on second and third, it was 92 (mph) and not 97 (mph), and he just couldn’t step on it,” Snitker said. “He wanted to keep going. He said, ‘I can pitch like this.’ And I was like, ‘I know you can, but I don’t want something else to go wrong.’ Our guys stepped up.”

Asked when he knew something was wrong with López, Murphy said: “You could feel it and see it on the scoreboard. I keep track of the velos on guys, and it was a little uncharacteristic. Obviously, they thought so, too, in the dugout. I know he was game to keep going.”

What did López feel?

“A little bit of tightness,” López said. “I’ve always felt like I’ve had the mobility and the ability to, when I need to reach back and throw 95, 97, to be able to do it, and I just wasn’t able to do that today, and I think that’s what ultimately led to the decision.”

It’s encouraging that López’s initial tests returned clean. He seemed to be in decent spirits. And Snitker’s tone appeared to be one of optimism. Still, the Braves will hold their breath until they know for certain.

“It’s something,” Snitker said. “But we’ll know more when we get him looked at a little more.”

After López departed the game, Jesse Chavez threw three scoreless innings. Then John Brebbia did the same. Luke Jackson tossed two scoreless frames to secure Atlanta’s 15th shutout of the season.

In July, López went on the 15-day injured list due to right forearm inflammation. This essentially became a helpful breather for the guy who transitioned back to starting pitching this season.

The Braves cannot afford to lose López, who has been one of their three best starting pitchers this season – along with Chris Sale and Max Fried. Atlanta has dealt with one injury after another, beginning with Spencer Strider’s season-ending elbow surgery in April. The team has since lost Ronald Acuña Jr., Ozzie Albies, Austin Riley and A.J. Minter. Albies and Riley could return this season.

After tossing a scoreless inning on Tuesday, López has a 2.03 ERA over 128 2/3 innings – his most since throwing 184 frames in 2019. Before his injured-list stint, the Braves regularly gave him extra rest between starts.

If the Braves need a starter, they can use Grant Holmes without putting López on the injured list. If they need to place López on it, then Bryce Elder, AJ Smith-Shawver or Bryce Elder could be options.

López didn’t seem too down, but he wasn’t happy about having to leave the game.

“Yeah, it was a little frustrating, especially just given the circumstances,” he said. “The position the team’s in, every game counts, we’re fighting for every victory over there, so whenever I start a game, I want to go out there and be able to finish it. And not being able to do that was frustrating. I said I wanted to go back out, but obviously they made the decision to pull me, and I understand why they did that.”