I currently have Eric Chavez on my fantasy team and he sucks ass and the thing that scares me about Chavez is the lineup around him which is horrible so any deal that you can get decent value for him is good.
I also have Loretta who has been quite disappointing thus far this season. Comming into today he was batting .275 with 0 HR's however he did go 5 for 6 today and boosted his BA to .299. Loretta has shown no power however he does have 6 stolen bases this season which is 3 away from his career high which has been a nice surprise. With Loretta you know you'll get a good average and a good amount of runs.
Loretta >>> Chavez (overall)
Matsui is an interesting case, a lot people felt this would be the year that Matsui starts hitting for power but so far this season he really hasn't shown it seeing how he only has 3 HR plus a .233 avg. to boot. He has pretty much sucked so far this season. You should expect him to catch fire some time soon and begin his climb closer to his home run total from last year of 31. Also his avg. should end up around .280 and he will pick up 100 RBIs. So Matsui this year will probably end up giving you .280, 30+ HR, 100+ RBI, 90 runs and 1 SB.
Rollins' only real asset is his SBs, he has been terribly inconsistent over his career. He never had a real high avg before last year when he batted .289 and scored 119 runs which was the first time he has ever had 100+ runs in a given year. Rollins isn't going to hit many HRs look for about 15 this season. So Rollins this year will probably end up giving you .265, 15 HR, 65 RBI, 90 runs and 35+ SBs.
Matsui >>> Rollins (avg, HR, RBI)
Matsui = Rollins (runs)
Rollins >>>>> Matsui (SB)
So in the end Chavez is worthless, Loretta is very good and Matsui is better than Rollins at everything except SBs.
My Opinion: Make the trade.