The 24-year-old lefty reliever has been recovering from shoulder inflammation, and Tankersley is making strides toward being ready for the 2007 season.
A primary eighth-inning setup reliever, Tankersley will next throw a bullpen on Friday, and if that goes well, he is slated to toss live batting practice on Sunday.
The target date to get him into Grapefruit League competition is March 27.
"I feel I could be ready for [Opening Day], but that's not my decision," Tankersley said.
In terms of throwing the ball, Tankersley said: "I'm not holding back. I trust my arm right now."
The Marlins open the regular season on April 2 against the Nationals in Washington, D.C.
The team has been hopeful to get him about six or seven innings of work before he pitches in a regular-season game.
There is a chance Tankersley could open the season on the disabled list, retroactively, meaning he could be reinstated after a few games.
As a rookie in '06, Tankersley went 2-1 with a 2.85 ERA, appearing in 49 games. He could factor into the closer role as the season progresses.
Joe Frisaro is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.