The four players mentioned were not incoming freshmen. One JC transfer senior, one junior, and two sophomores. One of the sophomores had redshirted his freshman year.
LSU had 38 rostered players last year, and lost 4 seniors. Six juniors were drafted, but 2 returned for their senior year. There were 12 recruits for this year; 2 were drafted in the early rounds and didn't make it to campus, 4 others were drafted late and are on the 2009 roster.
Taking into account the above additions and subtractions, LSU ended up with 40 players, and needed to reduce by 5. I don't know where the 5th player went.
Had the the 2 seniors not returned and if a couple more of the drafted recruits decided to go pro, they would have been pretty close to the 35. (The football player is currently listed on the roster of 36 names, so they may not have to cut anymore.)
My own opinion is that schools need not carry 35, and it would be nicer if they didn't recruit to handle the contingency that fewer players than expected arrived at campus. But in the spectrum of behavior of college baseball teams, LSU didn't go overboard.