A couple of pitchers the Mets are hoping can contribute to the big-league club at some point will begin minor-league rehab assignments this week.  According to Adam Rubin both Chris Young and Jenrry Mejia will pitch for the St. Lucie Mets this week.  It will be the first official action for both since Young underwent shoulder surgery and Mejia Tommy John surgery last spring.  Both surgeries took place on May 16, 2011.  Mejia is schedule to pitch Wednesday for St. Lucie and Young is scheduled for Thursday. Mejia last pitched in AAA Buffalo's starting rotation to begin the 2011 season before requiring the surgery.  While many feel his long-term future could be in the Mets bullpen he is expected to be stretched out as a starter so that he may be able to help out in the majors as either a starter or reliever this year.  Then his long term position will likely be re-evaluated this offseason.  There is no expected pitch count for Mejia, who was actually forced to stop a bullpen session a few weeks ago because coaches believed he was over-throwing.  Mejia was optioned to the minors during spring training and so technically he is on Buffalo's disabled list.  There is no known time-frame for how long Mejia will rehab in St. Lucie before most likely rejoining the Buffalo rotation.  There is also no time frame for a major league appearance this year, but barring a set back it's likely Mejia will return to the majors at some point this year. As for Young, he is scheduled to throw 75 pitches, although that number could easily increase to 80 or 85.  After pitching great for the Mets last April losing Young to shoulder surgery was a big blow, and now that Mike Pelfrey is out for the year the Mets are hoping that Young can return to their rotation and regain the form he had for them last April.  Young is on a minor league contract and so technically on Buffalo's disabled list, but is not on the 40-man roster.  As soon as his pitch count is high enough, assuming he is effective in his minor league starts, Young will likely be in the Mets rotation.  That should take at least three or four starts, although some may be at the higher levels of the minor leagues.  If all goes well Young could be back in New York by the end of May or early June.