The Padres quest to improve the worst offense in baseball has been one of the biggest storylines of the off-season. That story added another chapter Thursday night.

The San Diego Padres have acquired All-Star catcher Derek Norris from the Oakland Athletics. In exchange, San Diego will send starting pitcher Jesse Hahn and reliever R.J. Alvarez to Oakland. The Padres will also receive minor league pitcher Seth Streich and an international signing slot. The move was first reported by Mark Feinsand of the New York Daily News.

Norris, 25, made his first All-Star team last year, as he posted a very solid triple-slash of .270/.361/.403, with 10 home runs and 55 RBI’s in 127 games. Norris made $505,000 last year, and won’t be eligible for arbitration until the 2016 season. Norris is the third major acquisition the Padres have made this off-season, after trading for Matt Kemp and Wil Myers.

In exchange, the A’s acquire promising young starter Jesse Hahn. Hahn was acquired by San Diego last spring in the Logan Forsythe deal with Tampa Bay. Hahn sported a 7-4 record in his rookie season, with a 3.07 ERA in 14 games (12 starts). Hahn, also 25, showed a ton of poise and potential in his brief tenure in San Diego. Hahn was projected to be the Padres 4th starter next season.

Alvarez, 23, was acquired by San Diego in last year’s Huston Street deal. He earned a September call-up, and impressed in his 10-game stint in a Padres uniform, posting a 1.13 ERA in 8 innings. Alvarez also had a 1.25 in Double-A with seven saves last season.

Streich, 23, was the A’s 6th round pick in 2012, out of Ohio University. He pitched in High-A Stockton of the California League last season, and posted 3.16 ERA in 22 starts.

The international slot bonus can also come in handy, as A.J. Preller has been praised for his efforts in international scouting.