Fulchino, 32, is 9-10 with 21 holds and a 4.84 ERA in 163 relief appearances over five seasons with the Marlins, Royals, Astros and Padres.
Joaquin, 24, pitched each of the last three seasons with the Giants, posting a 1-0 record with a 5.40 ERA in 19 relief appearances.
Maldonado returns for his third season in the Nats' organization. The 32-year-old has appeared in 25 big league games over three seasons with the Pirates and Nationals (2010).
Blanco, 27, hit a combined .260 with 26 runs, 13 doubles, a triple, two home runs and 16 RBIs over the last two seasons with the Rangers. The switch-hitting infielder has played parts of six seasons in the Major Leagues with the Royals, Cubs and Rangers.
Hoffpauir hit .281 with five home runs and 34 RBIs in 91 games this past season with Triple-A Tucson. The 28-year-old has appeared in 21 games with the Cardinals and Blue Jays.
Tracy, 31, joins the Nationals after playing the 2011 season with the Hiroshima Toyo Carp of Japan's Central League. The left-handed-hitting Tracy hit 79 home runs over seven seasons with the D-backs, Cubs and Marlins.
Carroll, 29, has logged big league time in each of the last five seasons with the Marlins and Brewers. Last season, he batted .270 with 16 home runs, 63 RBIs and 11 stolen bases in 117 contests with Triple-A Nashville and Pawtucket.
Michaels, 35, has batted .263 with 59 home runs and 299 RBIs during his 11 Major League campaigns with the Phillies, Indians, Pirates and Astros.
Paul hit .255 with two home runs, 20 RBIs and 16 stolen bases in 128 games last season with the Dodgers and Pirates. Paul, 26, has played parts of three seasons with those clubs.
The Nationals also extended Spring Training invites to right-hander Rafael Martin, catcher Sandy Leon and outfielder Corey Brown. Of the three, Brown was the only one who played with the big league club in 2011. Martin has a chance to work out of Washington's bullpen in '12.
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.