The Seattle Mariners spiced up a relatively quiet trade window by acquiring Cincinnati Reds ace Luis Castillo in a blockbuster trade on Friday night.Castillo will reinforce a Seattle bullpen that already includes reigning Cy Young Award winner Robbie Ray. They also have young and dependable pitchers in Logan Gilbert and George Kirby.However, the price the Mariners had to pay to land the All-Star RHP was significant. Seattle sent three of their top five prospects in return for Castillo.Seattle Mariners@MarinersAdding another ace. We’ve acquired All-Star RHP Luis Castillo from the Reds in exchange for IF Noelvi Marte, IF Edwin Arroyo, RHP Levi Stoudt and RHP Andrew Moore. atmlb.com/3bcyApu95071320Adding another ace. We’ve acquired All-Star RHP Luis Castillo from the Reds in exchange for IF Noelvi Marte, IF Edwin Arroyo, RHP Levi Stoudt and RHP Andrew Moore. 📰 atmlb.com/3bcyApu https://t.co/6H2KXbbpFc"Adding another ace. We’ve acquired All-Star RHP Luis Castillo from the Reds in exchange for IF Noelvi Marte, IF Edwin Arroyo, RHP Levi Stoudt and RHP Andrew Moore." - Seattle MarinersShortstops Noelvi Marte and Edwin Arroyo, alongside right-handers Levi Stoudt and Andrew Moore, are headed to Cincinnati.Marte is the Mariners’ No. 1 prospect, while Arroyo and Stoudt are No. 3 and No. 5 respectively. Hence, fans are not impressed with Seattle compromising their farm system for one player.Jack Alcala@HesiSensei@Mariners we just traded noelvi marte for 2 years of castillo32@Mariners we just traded noelvi marte for 2 years of castilloKJ@thegentleman4@Mariners this is an L of massive proportions11@Mariners this is an L of massive proportionsChuck Battis@chattis33@StatsOnFire @HesiSensei @Mariners It’s not just about what the prospects turn in to. You gave up insane prospect value in one trade to move into being the 5th best team in the AL8@StatsOnFire @HesiSensei @Mariners It’s not just about what the prospects turn in to. You gave up insane prospect value in one trade to move into being the 5th best team in the ALHowever, some Seattle fans are absolutely ecstatic over their newest acquisition. At the end of the day, Castillo is a world-class ace. It would be rather foolish to not feel excited about his arrival.Steve@MarinersSteve@Mariners If your calling for Jerry's job after this, get the fuck out of here.We got Castillo2821@Mariners If your calling for Jerry's job after this, get the fuck out of here.We got CastilloSami Jarjour@SamiOnTap@Mariners If you’re crying about Marte. Get out of here. Not everyone is JRod. We got a fucking Ace. Lets go!!!5136@Mariners If you’re crying about Marte. Get out of here. Not everyone is JRod. We got a fucking Ace. Lets go!!!DawgProcess (#1 Berhalter Supporter)@DLock4MVP@Mariners Breaking news: you gotta trade something to get something! losing arroyo and marte sucks but so worth it56@Mariners Breaking news: you gotta trade something to get something! losing arroyo and marte sucks but so worth itLet's not forget that Castillo is an accomplished pitcher. He is averaging a 2.86 ERA in 14 starts this term.The 29-year-old has spent his entire career with Cincinnati and has compiled a 3.62 ERA in 137 starts across six seasons. He is a two-time All-Star. Prospects could be great in the future, but Castillo already is.Luis Castillo could be making his Mariners debut against the Yankees The Mariners had to hold off intense competition to land Castillo, with a dozen other teams believed to be in the mix. The New York Yankees considered him their number one RHP candidate for this window.That will now likely make for an awkward debut for Castillo next week, when the Mariners take on the Yankees in the Bronx.Dorion..🅰️..Ⓜ️ .. 71421@nyy_lol@Mariners My favorite part about this is that the Mariners will face the Yankees next week and Castillo will own them again 🤣🤣🤣5@Mariners My favorite part about this is that the Mariners will face the Yankees next week and Castillo will own them again 🤣🤣🤣The Mariners currently occupy the second AL Wild Card sport. Their starting rotation has a 3.68 ERA this term. Only six teams in the Majors have done better.Castillo’s addition certainly enhances their postseason chances and expectations. Losing top prospects is never ideal, but for a player of Castillo’s caliber, it should be worth the price.