To make room on the 40-man roster, the Nationals will transfer right-handers John Patterson and Jason Simontacchi from the 15-day disabled list to the 60-Day DL. In addition, left-handed pitcher Micah Bowie is expected to be reinstated from the 15-day DL on Tuesday.
Detwiler and Maxwell are the most intriguing players on the list. They are two of the team's top prospects. Their main job will be to watch and learn how the game is played the Major Leagues.
Detwiler and Maxwell most likely will get very little playing time because Washington wants to see what players such as pitchers Jason Bergmann and Matt Chico and outfielders Wily Mo Pena and Nook Logan can do in starting roles.
It also was pointed out by both general manager Jim Bowden and manager Manny Acta that the team wants to continue to play the veterans because most of the National League East teams they are facing are in a pennant race.
"We are bringing them up here and we'll see what happens," Bowden said. "Even if Detwiler doesn't pitch much and Maxwell is just pinch-running or being [a defensive replacement], it will be a positive building experience for their development."
Detwiler, who will wear No. 33, becomes the third Nationals player -- closer Chad Cordero and third baseman Ryan Zimmerman are the others -- in the last five years to be drafted and be promoted to the big leagues in the same season.
Detwiler, the sixth overall pick in the 2007 First-Year Player Draft, went a combined 2-2 with a 3.51 ERA in nine appearances -- eight of which were starts -- for Class A Potomac and the Rookie-level Gulf Coast Nationals.
"We have been impressed with Detwiler the last couple of outings. He is making progress. He was the pitcher we felt was closest to the big leagues. It would be a positive thing for his development -- getting him to the big leagues," Bowden said.
In Maxwell, the Nationals see him as their future center fielder. He was clearly the best position player in the Nationals' Minor League farm system.
Maxwell, who was Washington's second selection in the 2005 First-Year Player Draft behind Zimmerman, combined to hit .281 with 27 home runs, 83 RBIs and 35 stolen bases this season for Potomac and Class A Hagerstown. Maxwell is the only player in Minor League Baseball to record at least 25 doubles, 25 home runs and 25 stolen bases in 2007.
"We are developing here. We felt from the developing prospective, this would be a move that would be helpful for his development," Bowden said.
Albaladejo posted a 0.78 ERA (two earned run in 23 innings pitched) in 14 appearances with Triple-A Columbus after joining the Clippers the last week of July. Albaladejo, who also pitched for Double-A Harrisburg, fanned 8.3 batters per nine innings pitched en route to a .195 batting average against (42-for-215) in 2007.
Bowden said there were strong feelings from farm director Bobby Williams, Columbus manager John Stearns and Minor League coordinator Tim Foli that Albaladejo should be given a chance.
"They were very adamant that he deserved that opportunity. It took a lot of debate. You have to be careful with numbers," Bowden said.
Munoz, 25, is considered a lefty specialist and the club wants to see if he has a future in that role. Munoz went 3-1 with a 2.56 ERA in 54 appearances with Columbus of the Triple-A International League, where opponents hit .229 against him.
Langerhans, 27, rejoins the Nationals after clearing waivers on August 22. In 13 International League contests with Columbus, Langerhans hit .255 (12-for-47) with two doubles. Langerhans hit a combined .153 in 108 big league games with Washington, Oakland and Atlanta this season.
Before being sent down, Langerhans' playing time was reduced significantly because of the emergence of Logan in center field. The Nationals are hoping that Langerhans shows more patience at the plate. He is known to swing and miss at high fastballs.
Bowie missed a little over two months because of a left hip injury. He was a starter at the time of the injury, but will return in the Nationals' bullpen. Bowie was 4-3 with a 4.39 ERA before the injury.
Missing from the list of callups are left-handers John Lannan and Billy Traber. Both of them were expected to be promoted to the big leagues, but there was a change of heart within the organization.
In Lannan's case, the team decided to shut him down completely after pitching over 150 innings for the season. The original plan was to have him pitch out of the bullpen.
"We wanted to shut him down and send him home and get ready for next year," Bowden said. "We think John Lannan has a chance to be one of our five starters out of Spring Training. We are shutting him down to protect his future and the Nationals' future."
As for Traber, budgetary reasons and the fact that he was outperformed by Albaladejo and Munoz in Columbus were factors in his not being recalled.
"Those decisions were tough," Bowden said. "You can't bring everybody up. We certainly would have liked to bring Billy Traber up, but we have certain budgetary responsibilities that we have. I think Billy has a chance to be with our staff next year -- [he] may or may not. We clearly know what we have with him."
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.