In an 11th-hour move aimed at bolstering their lineup for the stretch run, the Orioles acquired power-hitting outfielder Michael Morse from the Seattle Mariners on Friday afternoon in exchange for minor league outfielder Xavier Avery.

Morse adds a much needed right-handed bat to a team fighting for a second straight postseason berth .He can fill the Orioles’ designated hitter spot — the club’s designated hitters are were batting just .220 this season entering Friday — and also see time in left field against left-handed pitching. The Orioles have struggled against left-handers, batting just .247 against lefties compared to .271 against right-handed pitching entering Friday.

“We needed a little more punch in our lineup and we need it now,” Orioles executive vice president of baseball operations Dan Duquette said. “Morse is a big, strong, physical guy with experience. He's been in the playoffs before and he has power.”

Morse, 31, had previously been a trade target of the Orioles, and the club was finally able to acquire him after he was placed on trade waivers and claimed by the Orioles on Wednesday. The clubs had 48 hours to make a deal — the deadline was Friday at 1:30 p.m. — or Seattle could have revoked Morse from waivers and kept him. Duquette said negotiations “went down to the wire.”

Orioles manager Buck Showalter said Morse, who was with the Mariners in Houston on Friday, will join the club Saturday or Sunday.

“He presents options for us,” Showalter said. “As you can see, it seems like every left-hander alive and breathing is going to come out of the woodwork. He could help us with that some.

“He’s somebody we’ve thought about off and on. He’s been on the radar. It’s something that Dan and I have been talking about and it kind of came together in the end. It came together pretty quickly when they agreed on the player coming back.”

Morse becomes a free agent at the end of the season, and the Orioles are on the hook for roughly $1.25 million of his remaining contract.

After being traded to Seattle from the Washington Nationals in January, Morse has batted just .226/.283/.410 with 13 homers and 27 RBIs in 307 plate appearances this season. He had a fast start to the 2013 season, hitting eight homers in by the end of April, but he missed five weeks with a quad injury.

“Hopefully, he will get hot like he did in the beginning of the year,” Duquette said. “He liked the area. He likes our ballpark.”

Morse is a career .284/.338/.479 hitter and had his best season with the Nationals in 2011, when he hit .303/.360/.550 with 31 homers and 95 RBIs in 146 games.

Morse has a .283/.298/.457 line in 15 career games at Camden Yards.

Avery, 23, played 32 games with the Orioles last season, hitting .223/.305/.340 with six doubles, one homer, six RBIs and six stolen bases in nine attempts. But he was among the club's first cuts this spring and began the year at Double-A Bowie.

“It’s a tribute to our scouting and player development that we developed a player to the point that we could get Michael back for him,” Showalter said. “It’s a good spot for him. I’m happy for Xavier. He’s really come on here at the end and he did well in Double-A this year. I’m sure they saw him good the last couple of weeks. He fits them good.

Avery, the Orioles’ second-round draft in 2008, batted .237/.312/.312 with 12 doubles, two triples, two homers, 23 RBIs and 17 steals in 23 attempts at Triple-A Norfolk this season.

Over the past month, the Orioles have traded three of their top 10 prospects heading into the year: Avery, infielder Nick Delmonico and outfielder L.J. Hoes in deals that have netted Morse, veteran reliever Francisco Rodriguez from the Milwaukee Brewers and right-hander Bud Norris from the Houston Astros. The Orioles also dealt right-handers Jake Arrieta and Pedro Strop in a July 2 trade in which they acquired right-hander Scott Feldman from the Chicago Cubs.

“I’ve been here when we were big-time sellers, but not even sellers because nobody wanted nobody from here,” said Orioles center fielder Adam Jones, who was a teammate of Morse’s in Seattle in 2006 and 2007. “But now we’ve got the opportunity to be buyers and it’s not like we’re going out and increasing payroll by $25-30 million. We’re going out and getting guys who are very good pieces to teams and guys who can really help. I think Morse can come here and I think he can be very impactful.”

The Orioles had also made a waiver claim on Minnesota Twins outfielder Josh Willingham, but the teams couldn’t complete a deal. Willingham was a costlier target than Morse, as he is in the second year of a three-year, $21 million deal.

O’s sign veteran 1B Johnson

The club also signed veteran Dan Johnson to a minor league deal Friday after the first baseman opted out of his deal with the New York Yankees. Johnson will likely join the club when rosters expand on Sunday.

The 34-year-old Johnson recorded a .253/.379/.447 slash line with 21 homers and 69 RBIs with the Yankees’ Triple-A club in Scranton/Wilkes-Barre. He hit .311/.436/.544 with five homers and 13 RBIs in 26 August games.

The left-handed hitting Johnson is best known for having two of the biggest pinch-hit homers in Tampa Bay Rays history. In the final game of the 2011 regular season, he hit a two-out, two-strike, game-tying homer in the bottom of ninth that helped send the Rays to the playoffs.