The Call-Up

The Call-Up: Nate Karns

The Nationals call up a pitching prospect to fill in for the injured Ross Detwiler.

The Mariners replace Dustin Ackley with Franklin, Seattle's fourth-best prospect on our offseason rankings.

Desperate for a starter, the Jays call up their no. 2 pitching prospect from Double-A.

The Orioles summon one of baseball's top pitching prospects to plug a hole in their rotation.

The Padres call up the Texas League's most dominant starter.

The Cardinals look for bullpen help from their top starting pitcher prospect.

Meet the Marlins' new right fielder.

The Rockies pull the trigger on a long-awaited promotion.

The Padres summon a southpaw prospect to bring some relief to their overtaxed staff.

The Tigers call up a hard thrower.

The Phillies summon a replacement pitcher from the farm.

An injury to Ryan Zimmerman clears room for the Nationals' top prospect for the second straight season.

The Red Sox summon a groundballing righty to face the Royals.

The skinny on the Brewers' new starter.

The Reds have called up pitching prospect Tony Cingrani to start in place of Johnny Cueto

Arcia might only be up for a few days, but a strong first impression could lead to an everyday outfield role before long.