Holland was named Oilers GM last May after 30 years with the Wings organization. He traded for Detroit defenseman Mike Green on Sunday.
Holland has Edmonton in the mix in the Western Conference, currently sitting in second place in the Pacific Division after missing the playoffs the past two seasons.
The Oilers got their biggest boost when Connor McDavid returned to the lineup Sunday after missing two weeks with a quadriceps injury. The Oilers also have the leading scorer in the league in Leon Draisaitl, but they've needed help for a while.
The Oilers also added center Tyler Ennis on Monday, acquiring him from the Ottawa Senators for a 2021 fifth-round draft pick, according to reports. Ennis, 30, has 14 goals and 19 assists in 61 games this season, his first in Ottawa after signing an $800,000 deal in July.
Athanasiou, 25, has 10 goals and 14 assists this season after having a career year with 30 goals and 24 assists last season.
His regression came amid an ongoing rebuild for the Red Wings, who have crashed to the worst record in the NHL this season (34 points in 63 games) and are in the midst of a four-year postseason drought, their longest since 1979 to 1983.
They have compiled a haul of draft picks, though, entering trade season with nine picks in the first three rounds of the next two drafts.
Athanasiou is a league-worst minus-45 this season, on pace to sport the worst plus-minus since Rico Fata was a minus-46 in 2003-04. Athanasiou will become a restricted free agent after this season, completing a two-year, $6 million deal.
Gagner was the sixth overall pick in the 2007 draft by Edmonton and is in his second stint with the team. He also played for Vancouver Canucks, Arizona Coyotes, Philadelphia Flyers and Columbus Blue Jackets.
His best season came with the Blue Jackets in 2016-17 when he had 51 points. He has only five goals and seven assists in 36 games this season while playing a third-line wing role.
He will be an unrestricted free agent after the season.
Kuffner has played 10 games with Detroit and hasn't scored.
Holland also said Monday that defenseman Kris Russell has been placed on long-term injured reserve. The 32-year-old has been in the concussion protocol and hasn't played since Jan. 29.