In the waning moments of Monday's deadline, the Dodgers also acquired two relievers to improve their bullpen.
In a trade with the Toronto Blue Jays, the Dodgers received right-handed Jesse Chavez and cash considerations in exchange for right-hander Mike Bolsinger. Chavez, 32, has a 4.57 ERA in 39 appearances this season.
The Dodgers are also bringing right-handed reliever Josh Fields to Los Angeles after a trade with the Houston Astros. The deal between playoff contenders sends Cuban first baseman prospect Yordan Alvarez to Houston. Fields, 30, had a 6.89 ERA in 15 games for the Astros this season.
Reddick, who will be a free agent after this season, was batting .296 with eight home runs and 28 RBIs in 68 games for the A's this season. He missed nearly five weeks with a fractured thumb.
In a statement posted on his Twitter account, Reddick thanked the Athletics organization and told fans, "To my people in the RF bleachers: NEVER CHANGE."
Can't wait to start my journey in Dodger blue!!! Let's win a pennant race! .@BMcCarthy32 I need a profile pic.— Josh Reddick (@RealJoshReddick) August 1, 2016
The Dodgers need offensive production from their outfielders, especially in right field. Through games of this past weekend, Dodgers right fielders had a .729 OPS, ranking 12th in the 15-team National League. Dodgers right fielders had scored 55 runs (10th in the NL) and had driven in 46 (11th).
"Reddick is a two-way player, he has power, he's a Gold Glove-caliber outfielder," Dodgers general manager Farhan Zaidi said. "I think he's going to help this team a lot. He was as good as any player available in this trade market."
Hill, who is 9-3 on the season with a 2.25 ERA in 14 starts, is on the 15-day disabled list, retroactive to July 20, because of a blister. He will be a free agent after this season.
Hill will be eligible to join the Dodgers by Saturday, the next time they need an additional starter. They have been operating with four starters, forced into the setup because of injuries and innings limits on youngsters, while able to pull off the arrangement for a week and a half because of a number of recent off days.
The Dodgers filled two needs without including their top pitching prospects in a trade. Julio Urias, a left-hander who will turn 20 on Aug. 12, already has nine games of major league experience this season. He struggled early but ultimately showed some promise while compiling a 4.69 ERA. Urias likely will rejoin the Dodgers later this year as a reliever.
Another top pitching prospect the Dodgers retained was right-hander Jose De Leon. The soon-to-be 24-year-old has compiled a 3.83 ERA at Triple-A Oklahoma City.
The A's are still receiving some highly regarded arms in Monday's deal.
Holmes, the Dodgers' first-round pick (22nd overall) in the 2014 draft, was 8-4 with a 4.02 ERA in 20 games (18 starts) for Rancho Cucamonga, the Dodgers' Class A team in the California League. The right-hander is 20 years old.
Cotton, 24, was 8-5 with a 4.90 ERA in 22 games (16 starts) for Oklahoma City, the Dodgers' Triple-A team in the Pacific Coast League. The right-hander was drafted by the Dodgers in the 20th round in 2012.
Montas, 23, hasn't played this season. In June, the right-hander suffered a setback in his recovery from a right-rib resection procedure.