"Brett Myers boarded an airplane to South Florida last night, ready to rejoin the Phillies today and hoping to pitch by early next week. But a timetable set by the team was more conservative.An MRI in Philadelphia yesterday showed that Myers had suffered a Grade 1 strain of his right latissimus dorsi (back) muscle, a team spokesman said last night. The righthander is scheduled to throw a bullpen session on Tuesday, and the Phillies hope - but did not guarantee - that he will return by the end of the regular season.Reached by telephone yesterday afternoon, Myers told The Inquirer that he was optimistic about appearing in a game early next week."I think I could be ready by the homestand," which begins Monday, Myers said. "My strength is good."Myers' injury could have been a side effect of making five relief appearances in seven days after returning from the disabled list. The righthander did not pitch in a major-league game from May 27 to Sept. 5 after having right hip surgery."