With New York's NL East lead down to two games following a four-game sweep in Philadelphia, Mets officials watched Martinez throw about 53 pitches over 20 minutes before Friday's series opener at Turner Field.
General manager Omar Minaya said the three-time Cy Young Award winner may start for the Mets on Monday in Cincinnati. Martinez had surgery Oct. 5 to repair a torn rotator cuff and hasn't pitched in the major leagues since Sept. 27 last year.
If the Mets have any concerns Saturday, Martinez will start Monday for Class A Brooklyn.
Martinez felt better Friday than during his fourth rehab outing Monday for the St. Lucie Mets of the Class A Florida State League.
"I had better stuff, better command, better tempo," he said. "It's not uncertain, like the previous outing."
Martinez's fastball was in the 84-88 mph range Monday, when he gave up an unearned run and five hits in six innings. He said he wasn't concerned with his velocity.
"The better you feel, the more you want to push it," he said. "I don't want to fall into that trap."
Mets manager Willie Randolph said Martinez threw "crisp, nice and free" and said the throws appeared to be "effortless coming out of his hand."
Minaya called the bullpen session "very successful." Martinez pretended to be surprised that his workout drew so much attention.
"You're going to watch me throw a bullpen?" Martinez said to a reporter. "Really? A bullpen is a big deal? After all I've done?"
Oliver Perez is currently slated to pitch Monday but could be pushed back a day. Orlando Hernandez, in line to pitch Tuesday, has a sore tendon in his right foot and returned to New York following Thursday's game.