Has anyone started a season and had more rookies on their ML roster than most teams would? I'm wondering how season turned out with 5-6 rookies to start season. I was thinking of trying it with one of my teams. Normally I don't do that, but I am curious as to how team would fare? Was team hurting because having a lot of rookies kept them from being at least .500 team?

It all depends on their ratings. If their ratings are comparable or better than the alternative then bring them up if you want. There's no such thing as a rookie boost (or nerf).

I have done this several times. No issues except when they all want real money at the same time in 4-5 seasons.

Thanks guys.

How many years they played in the majors means nothing. Ratings are what to look for. If they are your best option then play them. A player plays to his ratings. Of course fielders affect pitchers as do the pitchers other teams use affect hitters.