Marte (SS) is MLB.com's 19th best prospect in baseball but he is also pretty far off, 20 years old in A+ ball. Edwin Arroyo (SS) is 93rd, 19 years old and in A ball. Stoudt is 25 in December, slowly recovering from TJ surgery, and has a 5.28 ERA in AA. Andrew Moore is a 23 year old relief pitcher they drafted in the 14th round last year who, while striking out a ton of guys, is also walking people at a pretty high clip in A ball (32.1 innings pitched 16.1 K/9 4.7 BB/9). Sure, three of their current top 5 prospects (1, 3, and 5) but their #1 (Julio Rodriguez) and #3 (George Kirby) from the beginning of the season are contributing in the majors right now.
edit: Matt Brash was their 4 prospect at the beginning of the year but has struggled so far and seemed to lose prospect status. So they have graduated 3 of their top 5 from the beginning of the year. Kelenic is still on the team and was recently a major prospect. Why not go for it? Logan Gilbert, Luis Castillo, Robbie Ray, Marco Gonzales, and George Kirby is a pretty good 1-5.
edit 2: Also forgot that they signed J.P. Crawford to a 5 year $51 million extension at the beginning of the season. He has 3 bWAR and 2 fWAR so far this year. Maybe they can develop another SS prospect by 2027?