MESA, Ariz. -- Cubs pitcher Ted Lilly, rehabbing from arthroscopic surgery on his left shoulder, was expected to throw to hitters on Thursday and may only need three starts before he could be inserted into the rotation.

Lilly went home to California on Sunday to be with his wife, Natasha, for the birth of their first child, Theodore Roosevelt Lilly IV. Cubs manager Lou Piniella said he talked to the new dad and Lilly was eager to throw live batting practice.

If all goes well on Thursday, Lilly will next throw a simulated game -- or "assimilated game," as Piniella calls it -- then start in a Cactus League game. Lilly will stay back in Arizona when the big league team breaks camp to get more work in.

"Larry [Rothschild, pitching coach] seems to think three starts will be enough," Piniella said. "That's why we're optimistic."

If the lefty does that, he could be in the Cubs' rotation by mid to late April.

Jeff Samardzija, competing for one of the vacancies in the rotation, will throw four innings of a Minor League intrasquad game on Wednesday at Fitch Park. Piniella is hoping to finalize the pitching by March 25.

Lefty Tom Gorzelanny, another starter candidate, threw a simulated game early on Tuesday on a backfield at HoHoKam Park.