Redding held Florida scoreless during the first three innings, but he felt some discomfort in his back as he began warming up in the bottom of the fourth inning. Redding decided to gut it out because the Nationals brought only six pitchers to the game.
Most of Redding's pitches in that inning were in the middle of the plate and the Marlins took advantage of the situation by scoring four runs.
The pain in Redding's back grew worse when he threw a pitch that went under the glove of catcher Paul Lo Duca for a passed ball. As Josh Willingham scored, Redding didn't even bother to cover home plate. Redding doubled over in pain and asked assistant athletic trainer Michael McGowan to come to the mound. Manager Manny Acta and pitching coach Randy St. Claire also headed to the mound. A few minutes later, Redding left the game and was replaced by left-hander Ray King.
"I was throwing the ball well [prior to the fourth inning], so I just thought it was something I could keep pitching through and it wasn't going to flare up," Redding said. "Unfortunately, every couple of pitches, it would get worse and worse. It prevented me from continuing to locate my pitches. Everything was down because I couldn't extend and I was cutting everything off.
"I tried to battle through it. Unfortunately, I couldn't make quality pitches and get the guys out as I was doing the first three innings. It looks bad because of the passed ball and I didn't make an attempted to cover home. I was in a situation where [the pain was] real sharp."
Redding is scheduled have a bullpen session on Tuesday and then to pitch in a Minor league game in Viera, Fla., on Friday. Five days after that, Redding is expected to pitch a regular-season contest against he Phillies in Philadelphia.
Before the injury, Redding was having a good spring. Entering Sunday's action, he had a 2.81 ERA. It's a carryover from the second half of last season, when he was arguably the Nationals' best starter.
"He has thrown the ball real good," Acta said. "He has a lot of confidence and he has good velocity. He has done a great job."
If Redding can't go, especially on April 2, look for left-hander John Lannan to make the start.
"Obviously, you have to be concerned, but we have options this year. It gives you more peace of mind," Acta said. "Maybe somebody will have to pitch with an extra day of rest. That's about it."
A year ago, the Nationals didn't have good options in at Triple-A Columbus. They relied heavily on Minor League free agents, who didn't have good track records in the Major Leagues. Now, the Nationals can rely on their prospects such as right-handers Collin Balester, Tyler Clippard, Garrett Mock and Mike O'Connor to help sometime during the season.
"Somebody will step in and we'll deal with it," Acta said. "We have some options now. We made a lot of progress compared to last year. It's a big difference. If [the Redding injury] happened at this late date last year, we would have been scrambling just to get a guy [in the rotation]."
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.