To add Denard Span, pictured, to their outfield and the top of their lineup, the Nationals parted with pitching prospect Alex Meyer. (David J. Phillip/AP)


In the process of replacing Michael Morse with Denard Span in their outfield this past offseason, the Nationals also had to weigh the long term as they essentially dealt 6-foot-9 right-hander Alex Meyer for fellow pitching prospects A.J. Cole, Blake Treinen and Ian Krol.

Meyer, traded straight-up for Span, is the kind of power arm the Minnesota Twins had been seeking. Baseball America ranked him as the No. 59 prospect in the game and the top pitching prospect in the Twins system (No. 4 overall). He didn’t disappoint in his Class AA debut Sunday with New Britain, as he allowed only one run in five innings while striking out eight at Richmond. Meyer gave up six hits and a walk in that outing.

So not only did the Nationals part with power when Morse went to the Seattle Mariners in a three-team trade, but they also had to lose Meyer and his 95-97 mph fastball to acquire the dependable leadoff hitter and center fielder they lacked. Meyer turned down $2 million from the Boston Red Sox out of high school in Indiana and signed for that same figure with Washington as the 23rd overall pick in 2011 out of the University of Kentucky.

At least the Nationals welcomed back a $2 million arm when they received Cole as the key part of their return in the Morse deal. The Oakland A’s added catcher John Jaso from the Mariners, while they sent Cole, Treinen and a player to be named (Krol) to the Nationals.

Cole, a 6-4 right-hander, signed for $2 million after Washington took him in the fourth round in 2010 out of a Florida high school. He was rated as the No. 57 prospect in baseball in 2011 but was one of the four players dealt to the A’s for Gio Gonzalez in December of that year. Cole has since fallen out of the top 100 prospects list, but he was third on the A’s rankings this past offseason.

In his first start at high-Class A Potomac on Sunday, the 21-year-old Cole struck out seven and walked one while allowing seven hits and four runs in 5 1/3 innings against Lynchburg.

“He threw the ball well,” Nationals farm director Doug Harris said. “Overall he threw strikes with his fastball and his secondary stuff had flashes of quality.”

Treinen, a 24-year-old right-hander, has struggled in his first two starts at Class AA Harrisburg (0-2 with a 15.26 ERA in 7 2/3 innings), but the Nationals like his athleticism and secondary pitches.

Krol, a 21-year-old left-handed reliever who joined the organization in March as the player to be named in the Morse deal, is off to a fast start at Harrisburg. Left-handers are hitting .143 off him as he has a 1.93 ERA through three appearances, covering 4 2/3 innings.

“He’s got a lively fastball with good finish,” Harris said. “His breaking ball has nice tilt and depth. He’s very aggressive and competes well.”