Reliever Sean Green appears close to a return to the Mets.

Green, the lone remaining player acquired from the Seattle Mariners in the J.J. Putz trade in December 2008, has made only one appearance for the Mets this season. He landed on the DL after an April 7 relief appearance against the Florida Marlins with what originally was diagnosed as a strained rib-cage muscle. Eventually, it was discovered Green actually had a cracked rib.

“Initially they thought it was a strained intercostal -- like a strained rib muscle,” Green said Monday, before Triple-A Buffalo opened a series against Lehigh Valley in Allentown, Pa. “I was down there [in Port St. Lucie] rehabbing that for about three weeks and it wasn’t getting any better, so I asked to get reevaluated and got another MRI and they saw the fracture. It was like a stress fracture. It was about seven to eight weeks off completely from that. It’s been a long process. I had to start over, from scratch.”

Green began a rehab assignment in the Gulf Coast League on July 15. Because those minor league stints last a maximum of 30 days for pitchers, the rehab stint should expire no later than Friday.

Green has a minor league option remaining, but it would seem nonsensical to burn his final one this year when the rehab assignment expires and keep him in the minors. Rosters are going to expand Sept. 1 anyway, so optioning Green would buy only two extra weeks off the roster. As a result, Green should be back within days.

“I’m close,” Green said. “I’m just waiting to see what’s going to happen.”

Green has returned to his standard low three-quarters arm slot, after going submarine with the Mets this year in spring training. He figured the change to the drastically lower arm angle probably this year resulted in the rib fracture.

“I would assume. It was a pretty drastic mechanical difference,” Green said. “I had success that way. And also I suffered an injury that was a little bit awkward. I figured I’ve only been doing the lower arm delivery for two months and I got hurt, so there’s no reason to keep doing that.”

Green is making $975,000 this season and is arbitration-eligible. There’s always a chance the Mets could trade or nontender him this offseason. But because Green is likely not due a pay raise off a lost season, it would seem reasonable to expect he could remain and be a factor in the 2011 bullpen.

Since joining Buffalo, Green has allowed five runs on nine hits and a hit batter while striking out four in 5 1/3 innings spanning five appearances.