PORT ST. LUCIE, Fla. -- Jon Niese has been pitching with soreness in his right knee since the end of last year, the left-hander acknowledged Friday, though he does not consider it a source of concern. Niese threw three scoreless innings against the Tigers on Friday.

"It was just a little sore at the end of the year," Niese said. "Just a little fatigue, but there's no issue."

The Mets hope that Niese, entering his age-26 season and the presumed beginning of his baseball prime, can eclipse 200 innings for the first time in his career. He will wear a brace on his right knee to assuage the soreness.

Mets still plan on Santana for Opening Day

PORT ST. LUCIE, Fla. -- The Mets still expect Johan Santana to be ready for Opening Day, though they have a contingency plan in place if he is not.

Jon Niese would start on April 1 if Santana is unable to go, manager Terry Collins said. But Collins reiterated that he ultimately expects Santana to take the mound at Citi Field, clarifying remarks he made on the radio earlier Friday.

"It's not doubtful," Collins said. "I just said if he is doubtful, we've got to come up with someone else."

Collins outlined a rough schedule that should allow Santana to pitch in Grapefruit League games by the middle of the month. The left-hander will throw long toss at 150 feet on Sunday, then at 180 feet on Tuesday. If all goes well, he will take the mound for live batting practice the following Thursday.

Presumably, Santana would then make his first Grapefruit League start on or around March 10, the date the Mets originally targeted when they shut him down with shoulder weakness.

It is a tight timetable, and any setback would probably prevent Santana from pitching Opening Day. But if the left-hander is not ready to go on April 1, he is still unlikely to begin the season on the disabled list.

"If he's not ready for Game 1, I think he'll be ready for Game 4," Collins said.

Santana threw two bullpen sessions upon arriving to camp, but Mets coaches observed a lack of arm speed in the second of them and shut him down from mound activity. Tests revealed no structural damage in Santana's surgically-repaired left shoulder, leading him to resume his long-toss program.

Duda sidelined with 'minor medical issue'

PORT ST. LUCIE, Fla. -- Outfielder Lucas Duda was a late scratch from Friday's lineup with what general manager Sandy Alderson termed a "minor medical issue." Duda had a doctor's appointment earlier in the day and, though he returned to the clubhouse, was unwilling to expound upon his condition.

Manager Terry Collins intimated that it was a minor issue, but said he was unsure if Duda would return to the lineup on Saturday. Marlon Byrd shifted to right field in Duda's absence, with Matt den Dekker entering the lineup in center.

"Lucas Duda will always try to play," Collins said. "But we'll see how he is in the morning."

Duda originally returned to the lineup Wednesday after missing the previous two games because the Mets did not think he was ready for game action. Duda, who fractured his right wrist moving furniture over the winter, went 0-for-7 with six strikeouts in his first two contests, before finishing 1-for-3 with a single on Wednesday.

Byrdak returns to Mets camp to continue rehab

PORT ST. LUCIE, Fla. -- In his continued push to resurrect his career, Tim Byrdak has returned to Florida to continue his rehab from left shoulder surgery. Byrdak, who aims to return to the Majors by July 1, will remain in Port St. Lucie after the Mets break camp.

"You get in that baseball atmosphere," Byrdak said. "Being gone since August of last year, it was tough to get everything going. You have the wife and kids. It's going to be a lot easier to get things done around here."

Byrdak, 39, showed up to camp for a few days in mid-February to throw in front of Mets staffers. He then returned home to Chicago, where he continued throwing four days per week.

The club's primary lefty reliever over the past two seasons, Byrdak underwent surgery in August to repair a torn capsule in his left shoulder. He briefly considered retirement but ultimately decided to push for a comeback, inking a Minor League deal with the Mets over the winter.