"We'll treat him, just to get it calmed down and a pain-free range of motion before we start strengthening," Reds head trainer Paul Lessard said. "Really, after a couple of days, it should be calmed down."
Chapman will stay off of a mound for about a week but could resume throwing after he feels better, according to Lessard.
"We're not concerned about it at all," general manager Walt Jocketty said. "It's probably affecting what he's doing right now. We'll let him settle it down a little bit and give Bryan [Price, the Reds' pitching coach] an opportunity to keep working with him when he gets better. We'll get him on a rehab assignment, then get him back."
Since his Aug. 31 debut last season, the left-handed Chapman's ability to routinely top 100 mph had fans oohing and aahing. But his results at points this season have often been blah.
Chapman has 20 walks and 15 strikeouts in 13 innings and a 6.92 ERA over 16 games.
"The last two weeks, I've been feeling some discomfort in my shoulder," explained Chapman through interpreter Tomas Vera. "I could not make the 100-percent effort that I want to, so I believe that was creating the fail of my command."
Chapman said he kept word of his discomfort to himself until Monday, one day after an incredibly off-key appearance. During Sunday's 9-7 Reds win over the Cardinals, he was handed a seven-run lead in the top of the ninth. Chapman proceeded to walk four of the five batters he faced, which led to a five-run rally. Of the 23 pitches Chapman threw in the game, only five were strikes.
"I thought I was going to be able to get better through time," Chapman said. "I felt that was going to help me. But it really did not. ... At the beginning, it was just a small pain, a small discomfort, and I continued to do all my workouts and my work. It was staying the same, but at the end, it started to increase a little bit."
Signed to a six-year, $30.25 million free-agent contract in January 2010 after he defected from Cuba, Chapman has been both a sensation and something of an enigma. His super-fast velocity came with the caveats of raw talent and some wildness.
Chapman began last season as a starter at Triple-A Louisville until the club converted him to a relief role with an eye on his helping the big league club down the stretch. He did just that while posting a 2.03 ERA in 15 games with five walks and 19 strikeouts. His velocity came as advertised, and he set a record by throwing a 105.1-mph pitch in a September game in San Diego.
This season, Chapman began with 12 consecutive scoreless appearances over 11 2/3 innings, with the best outing of his brief career coming on April 27 at Milwaukee. He earned the victory that day, throwing 1 2/3 scoreless innings, and he worked out of an eighth-inning bases-loaded jam. Of the 19 pitches Chapman threw, 17 were strikes.
Since then, Chapman has allowed runs in each of his past four games and has been charged for nine earned runs and 12 walks. Twice, he could not retire a batter.
"I saw some difference," catcher Ryan Hanigan said. "When I see him going well, I see consistent tempo, and I see it from the first pitch during his warmups all the way through his inning. That one day game, he started having trouble with his control. His demeanor was different. He looked like he wasn't right, and his tempo was off. And the next game, it looked like his tempo was a little too fast."
Reds manager Dusty Baker has been handcuffed at times because Chapman hasn't been durable enough to give the Reds repeated use on back-to-back days. During an April road trip in San Diego, the same place he set the velocity record, his pitch speeds were in the low-to-mid 90s after he threw four times in five days. Catcher Ramon Hernandez told Baker and Price to take the pitcher out.
Chapman was diagnosed with shoulder inflammation then, and he rested for five days after that road trip. He hadn't tipped off the club that he was bothered by anything. Baker told Chapman after the incident that he was on the honor system when it came to notifying the team if he wasn't feeling right.
"He wasn't as reluctant this time as he was last time," Baker said. "He's learning to be more honest about things. It's a slow process, but where he came from, they don't say much about anything. It's a cultural thing as much as it is a physical thing."
When Chapman's struggles resumed this month, Price worked with him on mechanics and pitch-release points. But the adjustments had yet to yield positive results.
The Reds' long-term plans for Chapman are likely to have him in their rotation, where he would work on a regular schedule. But that won't happen this year. Jocketty dismissed any notions that being a reliever has caused Chapman problems.
"I don't think it has anything to do with it," Jocketty said. "I've heard everybody talking about that, and it has nothing to do with it. He was fine out of the bullpen last year. He was fine out of the bullpen earlier this year. His mechanics just got out of whack a little bit, and we just need to get him back on course."
Without Chapman, the Reds are down to one lefty in the bullpen, Bill Bray. Right-hander Jose Arredondo, just activated from the DL on Sunday, has a better track record against lefty hitters than righties. But Chapman at 100 percent is clearly an advantage the Reds would like to have back, soon.
"He knows that he probably needs it, and we need it," Baker said of the break for Chapman. "Even if he comes back after 15 [days], we've still got a big four months to go. That's a long, two-thirds of the season left. It's better to take care of it now, and hopefully we'll have the Chapman that we know the rest of the season."