Ironically, Dahl's offense has fallen off but his defense is better than expected, go figure!
I think you stick with Rojas, Pache really doesn't show a lot of promise as a hitter, Rojas has a quick bat, he just has to learn the ins and outs of working a count.
Castellanos is the real problem, after two weeks where he looked acceptable, back to below replacement level play. I think at this point he's a .700-.750 OPS RF with below average defense, i.e., replacement at best.
Compare to Marchan, who merely has to put up .700 OPS to be ML starter quality, because he's a plus defender at a premium defensive position. He's developed alley power, that is, enough to keep OFs honest and allow him to hit for average, with his speed he just needs a BB% around 8-10% to hit that target.
The most perplexing player is Stott, he's not this bad as a hitter.