Ryan Madson said after Sunday night’s game that he’d been dealing with some discomfort before being called on by Manager Dave Martinez (John McDonnell/The Washington Post)

ST. LOUIS — Nationals Manager Dave Martinez didn’t know Ryan Madson was battling discomfort when choosing him to pitch that fateful ninth inning Sunday night. Martinez said he was “very” surprised to hear about it when alerted by club staff a few minutes after Madson revealed the discomfort to reporters in a somewhat surprising interview. Veteran players like Madson generally try to avoid talking about injuries in the aftermath of an inning like the one in which he surrendered a walk-off grand slam Sunday night at Wrigley Field. Fairly or not, explanations almost always feel like excuses.

“I just wanted to be out there and upfront with everybody as far as what’s going on and why some pitches are bouncing far in front of the plate. I just wanted it to be out there, be truthful about what’s happening,” Madson said Monday. “. . . [Today] I went in there and told him I need some treatment, instead of toughing it out and not saying anything. Because it just went past the normal everyday stuff for me. So that’s when I finally said something. But before that, I said I’m fine. Just give me the ball. I’m good.”

Martinez said he understood Madson’s inclination not to say anything. But given that he and Madson had been in direct communication for much of this season — more direct communication than Madson has ever had with a manager before, according to the reliever — Martinez was surprised he felt he could not be honest about his situation. The Nationals have already lost two closers to injury and desperately need Madson, which could have contributed to his reticence.

“Apparently he didn’t want to say anything, he wanted to pitch through it. I talked to him today, he said it’s one of those things. He feels like he can pitch through it,” Martinez said. “. . . I told him you’ve got to be honest with me and move forward. I just told him to let me know how he feels.”

Madson said he will begin taking anti-inflammatories which should help alleviate the swelling in his lower back. Apparently, that inflammation has contributed to the shooting pains that ran down his legs. He does not anticipate a disabled list stint.

“Just the progress that [Director of Medical Services Harvey Sharman] gets me to leads to me to believe it’s not bad. Create enough space and let that inflammation go down. He’s gotten the space and lined everything up good,” Madson said. “. . . Harvey will be able to keep everything straight.”

Asked whether Madson will continue to be his first choice as closer for this week’s series against the Cardinals, Martinez said he will use matchups to make that decision but “I can’t see why he couldn’t if he tells me he’s good.”

“I watched him yesterday. He’s throwing 97 miles an hour,” Martinez said. “Madson’s good, and he’s a big part of our bullpen. So if he’s available, he’s going to pitch high leverage situations.”

Still Martinez reiterated that he needs Madson to be honest about his status, whenever he feels trouble emerge — even if it’s in the bullpen. Martinez spoke to bullpen coach Henry Blanco after Sunday’s game to see if he had noticed anything. Blanco said he couldn’t tell anything was wrong with Madson, either. Martinez had called down to warm up Justin Miller before Madson hit his second batter and was planning to bring him in if Madson could not retire David Bote. He never got the chance.

So for now, Madson will remain a late-inning option, likely combining with Miller and Koda Glover in situations like Sunday night. But he will remain a wild card until his pain subsides and he establishes his command again.

In other, more definitive injury news, Anthony Rendon returned to the Nationals lineup Monday after missing two games with a sore wrist. He tested the wrist in the cage before the game and it passed, according to Martinez. Rendon played an inning at third as a defensive replacement Sunday.

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