Dunn is very likely going to be at least a 100 point upgrade in OPS over Murton. Having Murton put up a 780-800 OPS might be more cost effective, but we'd be better off spending to get Dunn to consistently put up a 900+ OPS. I wouldn't say he would be at least a 100 plus upgrade necessarily. Dunn has put up a 900 or more 2 out of the last 4 years-one of the years he didn't do that was this year. He's 89 points better than Murton this year. Murton's numbers still have room to go up, while Dunn is more likely to consistently stay around the numbers he's put up the last 3-4 seasons or so. Dunn is 26, Murton is 24. Dunn makes 7.5 million dollars this year, Murton makes 337,000. Murton plays better defense than Dunn (although Dunn is a little better than some of the mistakes we see him make on defense). Also, trading for Dunn would require more than Murton-so we have to factor in how valuable the other players we'd have to trade them would be, or how valuable those pieces would be in another trade (some of the players mentioned could be used to get Andruw Jones or possibly Tejada for example) It still might be worth the gamble, but it's certainly not an open and shut case. Why would you expect a 24-year-old Murton to improve but not a 26-year-old Dunn? Murton is more likely to improve IMO because he's coming off his first full season. His numbers have the chance to get better as he continues to learn the major league game. Dunn has been up for 6 seasons now. Here are his stats during that time 01 (only 244 at bats)-.262/.371/.578 02-.249/.400/.454 03-.215/.354/.465 04- .266/.388/.569 05- .247/.387/.540 06- .238/.368/.512 If he were 26 and had shown signs of improving steadily during his career, I would say he is more likely to keep improving. He is certainly young enough to improve, but his stats have been falling instead the last couple years (without any injury or something like that to explain it). Do I think his stats will keep falling? Not yet-I think he'll have a series of years that parallel either his 04, 05, or 06 numbers (some of each probably mixed in). Dunn definitely still has the chance to improve, but Murton just coming off his first major league season makes him far more likely to improve on this years numbers IMO. That's a good point, but it also fails to recognize that much of Murton's OBP is elevated by an very high BABIP. If that drops, then so would his OBP. I don't see much room for improvement in Murton's OBP for that reason. The only place where Murton could markedly improve is his SLG. Unfortunately, nothing in his minor league or college performance indicates that it is likely to come anywhere close to approaching Dunn's SLG. I like Murton; he's probably one of my favorite Cubs right now, but the improvement from Murton to Dunn in LF would be remarkable. If Murton could play RF, I'd like to have both in the line-up. I just doubt whether Murton could play RF, and if the choice is Dunn or Murton, that's a no-brainer.