Rodríguez lined an RBI double off the left-field wall in the third to put Seattle on the board.
When Rodríguez came to the plate again in the fifth, the Angels elected not to face him. Los Angeles intentionally walked the AL hits leader with a 2-1 lead and two outs, despite Ty France being on first.
Rodríguez, batting .389 since Aug. 1, is just the third player in the majors this season to be intentionally walked without an open base.
“He has been one of the best in the game,” Angels manager Phil Nevin said. “I’m not going to let him beat us.”
Cal Raleigh and Teoscar Hernández made the Angels pay.
After Los Angeles brought in reliever Jimmy Herget, Raleigh lined an RBI single to right field that drove in France, who slid into home plate to beat the throw from Brett Phillips. Hernández then followed with an RBI single that deflected off second baseman Brandon Drury’s glove, scoring Rodríguez for a 3-2 lead.
“I really credit our guys behind Julio,” Servais said. “We are a complete team. It takes guys behind the star. You need guys to step up and have big at-bats, and they did.”
Castillo (13-7) allowed two runs and three hits in a 104-pitch outing. He struck out eight and walked three. The All-Star right-hander has won seven consecutive decisions and hasn’t lost since July 14.
“He has been the rock,” Servais said. “He has put together just an unbelievable season after doing what he did last year to lead us into the playoffs.
“He’s the epitome of consistency.”
Los Angeles threatened against Justin Topa in the seventh, putting runners on first and second with no outs. But Topa escaped the jam, highlighted by a pickoff that caught Jordyn Adams in a rundown between second and third.
The Angels again put the tying run on second in the eighth, but Matt Brash struck out Matt Thaiss to end the inning and become just the fifth reliever in Mariners history with 100 strikeouts in a season.
Andrés Muñoz worked the ninth for his 13th save. Raleigh ended the game by throwing out Phillips at second base.
“What an awesome way to end the game for a catcher,” Servais said. “Cal has done the walk-off homer. Now he’s done the walk-off caught stealing.”
Phillips hit a solo homer in the third and Drury added an RBI double in the fourth. José Suarez (1-3) took the loss for the Angels, who used seven pitchers in a bullpen day.
Hernández extended his on-base streak to 28 games. It’s the longest on-base streak by a Mariners player since Robinson Canó went 34 games in 2016.
Angels rookie Nolan Schanuel reached base safely for the 20th consecutive game to start his career.
Angels star Shohei Ohtani missed his 10th consecutive game as he continues to deal with a right oblique strain.
Angels: OF Jo Adell is slated to play Friday for Triple-A Salt Lake in his first game since landing on the IL with a left oblique strain two months ago.
Mariners: OF Jarred Kelenic was out of the lineup for a second straight day after fouling a ball off his right foot in Monday’s game. X-rays were negative, but manager Scott Servais said they wanted to give him added rest with an off day Thursday.
Mariners RHP George Kirby (10-9, 3.48 ERA) goes against Dodgers rookie RHP Bobby Miller (9-3, 3.98) to begin a three-game set Friday at Seattle.