PITTSBURGH (AP) — The Pittsburgh Pirates, swapping outfielders at a rapid rate for the second successive season, sent starting left fielder Njyer Morgan to the Washington Nationals in a four-player deal involving outfielder Lastings Milledge and also shipped backup Eric Hinske to the Yankees on Tuesday.

The Pirates, who have pushed to restock a thin farm system by making numerous trades over the last year, get Milledge and reliever Joel Hanrahan from the Nationals for the fleet Morgan and left-hander Sean Burnett, a former first-round draft pick.

Earlier, they sent 2002 AL Rookie of the Year Hinske to the Yankees for minor-league right-hander Casey Erickson and outfielder Eric Fryer. The Yankees also get some cash to help pay Hinske’s $1.5 million salary.

Just as they did last season by dealing Jason Bay and Xavier Nady, the Pirates have traded two of their three starting outfielders before Aug. 1. They sent former NL All-Star center fielder Nate McLouth to the Braves on June 4 for pitcher Charlie Morton and two other prospects.

Though rumored for several days, the Nationals trade is somewhat surprising because the Pirates dealt Morgan — who turns 28 on Thursday — less than halfway through a promising first season as a starter. He is hitting .277 with 2 homers and 27 RBIs, only four fewer than No. 3 hitter Freddy Sanchez, and has 18 steals, although he has been thrown out 10 times.

Milledge, a former top Mets prospect, has played in only seven games with Washington while part of the season rehabilitating a broken right ring finger that required surgery in May. He is expected to join Triple-A Indianapolis before being called up by Pittsburgh later this month.

Milledge, 23, has more power than Morgan — he has 25 homers in 897 career at-bats — but has bothered frequently by injury problems that include a broken right hand, sore foot and groin strain. He hit .268 with 14 homers, 61 RBIs and 24 doubles in 138 games last season, earning him a spot on the cover of the Nationals’ media guide this season.

Still, Milledge was a major disappointment to the Nationals, who dealt two starters — catcher Brian Schneider and outfielder Ryan Church — to acquire Milledge from the Mets in November 2007.

The right-handed Hanrahan, 27, is 0-3 with a 7.71 ERA in 34 games — he was demoted from the closer’s job — and has a 5.30 ERA in 115 career games. Burnett, the Pirates’ top pick in 2000, is 1-2 with a 3.06 ERA in 38 games and has pitched in 96 games the last two seasons.

The 31-year-old Hinske hit .255 in 106 at-bats this season with nine doubles, one homer and 11 RBIs, playing right field, first base and third base. He was 8 for 24 as a pinch hitter and has been disappointed by a lack of playing time.

Through June 29 last year, he had 13 home runs en route to a 20-home run season with the AL champion Tampa Bay Rays. He won the rookie award with Toronto in 2002, when he hit .279 with 24 homers and 84 RBIs, and was a member of Boston’s World Series championship team in 2007.

The 23-year-old Erickson was 3-3 with a 2.25 ERA in three starts and 18 relief appearances at Class A Charleston this season. Fryer, also 23, hit .250 with 11 doubles, two homers, 24 RBIs and 11 steals for Class A Tampa after leading the South Atlantic League with a .335 average last year for West Virginia. He was obtained by the Yankees in February for left-hander Chase Wright.

To fill Hinske’s roster spot, Pittsburgh purchased the contract of 28-year-old outfielder Garrett Jones from Triple-A Indianapolis, where he hit .307 with 18 doubles, 12 homers, 48 RBIs and 14 steals.