The Mets had seen the radar gun readings, and how they spiked one day and dipped the next. They noticed the string of 90s, and 92s, and 94s -- and they noted the absence of 98s.

Through it all, their belief remained unchanged. The road from neck surgery is long and rebuilding strength takes time. The readings would improve. Eventually, they felt they would see the real Bobby Parnell.

Now, just two days into the regular season, that assumption might be in serious doubt.

Doctors discovered a partially torn ligament in Parnell's right elbow, the Mets announced during a day off Tuesday. The diagnosis could put the 29-year-old closer in line for elbow surgery.

Parnell raised red flags when he blew a save Monday. His fastball topped out at 94 mph, continuing a trend that began in spring training. After the game, manager Terry Collins reiterated that Parnell simply needed more time to recapture strength in his right arm.

"As Bobby said, it's a work in progress," Collins said. "He's got to build it up. He hit 95 in spring training. He hit 94 today. You know, he's gonna get there."

However, Parnell complained of tightness in his right forearm after the game. According to a source, it was the first time this spring that Parnell raised any concern about his arm. Soon thereafter, Parnell was at Manhattan's Hospital for Special Surgery, where doctors discovered the tear.

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For now, Parnell hopes to avoid surgery. He has opted for rehab, so he won't throw again for two weeks. He has also received a platelet-rich plasma injection, an increasingly common treatment designed to speed up the healing process.

But even if he circumvents the surgeon's table, he appears headed for an extended absence, a damaging blow to the Mets' 90-win hopes.

Since Sandy Alderson took over as general manager following the 2010 season, Mets relievers have consistently ranked among the worst in the National League. On Opening Day, Alderson pinned the bullpen's hopes of improvement on Parnell, who established himself last season in the closer's role.

Until a herniated disc in his neck ended his season in late July, Parnell saved 22 games and posted a 2.16 ERA in his first extended opportunity to close for the Mets. Throughout his recovery, Parnell consistently stated his intent to be ready for Opening Day.

But his diminished velocity prompted the Mets to consider a contingency plan. Collins explored limiting Parnell to no more than two consecutive appearances early in the season. For games when Parnell was unavailable, save chances would fall to 36-year-old Jose Valverde, who signed a minor-league deal for a chance to resurrect his career with the Mets. Valverde, who has 286 career saves, now is in line to close.

With Parnell expected to go on the 15-day disabled list, the Mets called up 37-year-old reliever Kyle Farnsworth. To add him, the Mets must make room on the 40-man roster, though they have yet to announce a corresponding move.

Notes & quotes: The Mets announced that infielder Wilmer Flores will join the team Wednesday with second baseman Daniel Murphy expected to officially go on paternity leave. Murphy missed Opening Day for the birth of his son, Noah . . . Jonathon Niese (left elbow inflammation) remains on track to pitch against the Reds on Sunday. During a simulated game Tuesday night in Port St. Lucie, Fla., Niese allowed four runs, including two earned, in five innings. The Mets expect to activate Niese from the disabled list Saturday.