ST. LOUIS -- Mets general manager Sandy Alderson was mum Thursday on a potential deal that would have sent left-hander Chris Capuano to the Red Sox as an emergency rotation patch.

"There are lots of conversations that take place involving lots of players," Alderson said. "I don't think it's really productive to talk about things that don't materialize."

Alderson would not comment on why the deal, first reported by the Boston Herald, never took place, though he did point to three discouraging factors: a lack of adequate compensation, a desire to finish the season as strongly as possible and a wish, potentially, to re-sign Capuano for next season.

In danger of missing the playoffs after holding a nine-game American League Wild Card lead earlier this month, the Red Sox certainly had reason to inquire. Though Capuano would not have been eligible for their playoff roster, he could have filled Boston's rotation vacancy Sunday against the Yankees. A Massachusetts native, Capuano is 11-12 with a 4.47 ERA in 31 games this season.

The left-hander was scheduled to start Thursday's series finale against the Cardinals.

Consummating a waiver deal this late in the season may be unusual, but it is not unprecedented. Six years ago, facing a similar playoff crunch, the Red Sox acquired reliever Mike Stanton in time for their final series of the regular season -- also against the Yankees.

"I would never rule out a trade or a contract extension or anything else that would come up from time to time," Aldersons said. "Why would we, if we could improve the club?"

Duda on bench as precaution, but feels good

ST. LOUIS -- One day after running into the right-field wall and subsequently leaving the game due to dizziness, Lucas Duda reported no ill effects from the episode. Though Duda remained out of the Mets' lineup Thursday as a precaution and was due for additional testing, he does not consider the issue serious.

"I felt good yesterday and I feel the same," Duda said Thursday morning. "I still feel good."

Regardless, the Mets have not yet ruled out a concussion and will continue to exercise caution with their right fielder. Partly due to the serious concussions endured in recent years by Mets players Ryan Church and Jason Bay, Major League Baseball has instituted a new set of protocols for head injuries, including the establishment of a seven-day disabled list.

Duda has never before suffered a concussion, reducing his risk for one.

Bay, who is battling flu-like symptoms, was also out of Thursday's lineup for a third straight game. Reserve outfielders Willie Harris and Mike Baxter manned the corner positions against the Cardinals.

Beato's tired arm due to reliever's approach

ST. LOUIS -- After receiving assurances Tuesday evening that he would not be asked to pitch, Mets reliever Pedro Beato did the improbable: he stood up, stretched his arm and began throwing a bullpen session.

Though not unusual behavior for relievers on their scheduled off-days, the episode was bizarre in that Beato has complained recently of a tired arm. Mets manager Terry Collins and pitching coach Dan Warthen have implored the rookie to cut back on his throwing, and still Beato has persisted.

"We've told him all along, 'You've got to back off the throwing,'" Collins said. "'You've only got so many bullets.' But he sees the veteran guys, Izzy [Jason Isringhausen] and all those other guys doing their daily throwing program, so he thinks he's got to do it."

As a result, Beato has posted a 6.38 ERA in 24 appearances since July 22, serving up a three-run home run Wednesday and forcing the Mets to abandon plans to send him to Winter Ball as a starting pitcher. Beato may still appear in games for the Mets down the stretch, but his recent struggles have soured his rookie season and altered the organization's long-term agenda for him.

"To have him say when the game's over that his arm's tired, I gave him all the chances in the world to have some time," Collins said. "So I'm a little disappointed that that was his answer."