Designated hitter David Ortiz told on Wednesday that his short rehab stint with Triple-A Pawtucket will begin Thursday as planned, marking another step in his long and winding road back to the Red Sox's lineup. Ortiz played in the third of three simulated/extended spring training games in Fort Myers, Fla., on Wednesday and reported no issues with the strained right Achilles tendon that so far has cost him 11 weeks of playing time. By late Wednesday afternoon, he was headed north for Pawtucket's home opener Thursday night. The 37-year-old Ortiz has told Red Sox manager John Farrell that he would feel comfortable returning to Boston after 25 to 30 at-bats for Pawtucket, which puts him on track to potentially rejoin the Red Sox for their April 19-21 series against the Kansas City Royals at Fenway Park. Farrell said the team is leaving the timetable entirely in Ortiz's hands. "His return date to us is still uncertain at this point,'' Farrell said before Wednesday's game against the Baltimore Orioles. "That's going to depend on David and how comfortable he feels in the box with his timing. "We will assume somewhere in the 20- to 30 at-bat range would be expected that he'll need." Ortiz has missed all but one game since injuring his Achilles last July. He began spring training on track to begin the season with the Red Sox, but soreness in his heel kept him out of Grapefruit League action and delayed his return. If he returns by the 19th, he will have missed the first 18 days of the season. "More than anything," Farrell said, "the last four, five days he seemingly turned the corner. More aggressive running the bases, the way he feels at the plate. He's in a pretty good place, all things considered."