Russell Martin hits a two-run home run against the Mets...

Russell Martin hits a two-run home run against the Mets at Yankee Stadium. (June 10, 2012) Credit: Getty Images

Russell Martin's back hasn't healed as expected. The catcher, sidelined three straight games with a sore lower back before returning Wednesday, did not start Thursday night, and it's not certain when he'll be back. "It's not worse but it's not quite right," he said. "I'm not moving like I'd normally be moving."

Martin did not give a timetable for returning but said he felt it prudent to give his back "a couple of days" to get better.

He said he'd "rather take a couple of weeks now" than aggravate the injury and need to take "a couple of weeks" later in the season.

Martin, whose average dropped to .193 when he went 0-for-4 Wednesday -- a game in which he had a collision at the plate while tagging out Casey Kotchman -- said his back felt "better than it did a couple of days ago." But he added: "At this point, I feel if I'm in the lineup, I'm not helping the team."

Joe Girardi said he doesn't see Martin needing a stint on the DL and isn't concerned at this point.

"We've been through it before with him," Girardi said. "Short term, we want to get it better. Long term, I feel he's going to be healthy and he's going to be OK. In my mind, this is not a DL case. He's available if I need him tonight."

Betances to Double-A?

GM Brian Cashman said Dellin Betances, who has struggled this season at Triple-A, likely will be sent to Double-A Trenton to try to get back on track.

The 6-8, 260-pound Betances, one of the Yankees' top prospects, is 3-5 with a 6.39 ERA in 16 starts. In 742/3 innings, he's struck out 71 but walked 69.

Another BP for Joba

Joba Chamberlain is scheduled to throw his second live BP session of his rehab Friday. Chamberlain, who could be back in early August, has been running full sprints for a couple of weeks. The word from Tampa is that his right ankle is showing no signs of the open dislocation he suffered March 22 in a trampoline accident.

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