Sobering word that outfielder Xavier Nady 22 is shelved with an appendectomy is accompanied today by the exciting news that prospect Lastings Milledge is in Flushing to take over while he’s gone (and maybe longer). Word is Milledge will dress in the reserved-for-African-American-sluggers No. 44 (and not 6, which is what we might have rooted for to bridge the homegrown power alley between Wright 5 and Reyes 7). We wish Nady the best for a speedy recovery and that young Mr. Milledge (we won’t ever get used to referring to him as Lastings, we don’t think) doesn’t wind up overwhelmed by the “can’t miss prospect” pressures felt by previous Met inhabitants of his uni — Jay Payton and Ryan Thompson.