(Photo credit: Erik Williams-Imagn Images)

Luis Castillo hasn't pitched out of the bullpen in a regular-season game in his 10-year career.

That's likely to change Tuesday night, when the Seattle Mariners plan to 'piggyback' starter Bryce Miller and Castillo in the second game of a three-game series against the visiting Chicago White Sox.

'That's how it's gonna roll,' Mariners manager Dan Wilson said Monday afternoon in announcing the club's decision regarding its rotation.

With Miller making his season debut last week after being sidelined by a left oblique strain, the Mariners went with a six-man staff for one trip through the rotation.

But with Castillo (1-4, 6.34 ERA) struggling and Emerson Hancock (3-2, 3.02) earning a spot during Miller's absence, the Mariners decided they'd put two starters together, like some teams do in the minor leagues.

The plan Tuesday is for the right-handed Miller (0-0, 3.38 ERA) to go four or five innings, followed by the righty Castillo for three or four. That could help a Mariners bullpen that has Matt Brash and Gabe Speier on the injured list.

Castillo's only previous relief appearance came in the deciding Game 5 of the American League Division Series against Detroit last October. He got the final out of the 14th inning and pitched the 15th, earning a 3-2 victory on Jorge Polanco's walk-off single.

'I think it's all going to be a little strange to him,' Wilson said of Castillo, the Mariners' highest-paid player at $24.15 million this season. 'But, you know, just appreciate the way 'The Rock' has taken this. He understands how important the team is, and I think that's the kind of guy he is, and that's the kind of guy he's been.'

The Mariners won the series opener 6-1 Monday as top prospect Colt Emerson got his first major league hit -- a three-run homer in the eighth inning.

Emerson, who was called up at the last minute Sunday from Triple-A Tacoma, had more than a dozen friends and family members in attendance Monday, including his parents, who flew in earlier in the day from Ohio.

'I can't believe it happened when they were here,' Emerson said. 'It's special, it really is. Honestly, I'm speechless. I'm really just happy that they were here, and so grateful that this is the way it happened.'

Julio Rodriguez also went deep for the Mariners, who snapped a three-game skid, and Bryan Woo pitched six scoreless innings.

Tristan Peters homered for the second consecutive game as Chicago lost for just the second time in the past nine games.

White Sox manager Will Venable was ejected by plate umpire Tripp Gibson in the third inning after an obstruction call gave Seattle a run.

Mariners catcher Jhonny Pereda was on first base with two outs when Randy Arozarena doubled to left. Pereda ran into the back of White Sox second baseman Sam Antonacci shortly after rounding second base. Pereda continued home and was thrown out easily, but the umpires huddled after the play and ruled Pereda was to be awarded the run.

'You know, obviously, there was obstruction there, and you get some protection, but when you're thrown out by 30 feet, it's not supposed to protect you like that,' Venable said.

The White Sox are set to start lefty Anthony Kay (3-1, 4.61 ERA) on Tuesday.

Kay has won his past two starts, the first of which came against the Mariners in Chicago on May 9. He gave up one unearned run on three hits over five innings in a 6-1 victory. He followed with a 6-2 win Thursday against visiting Kansas City, as he allowed two runs on six hits over six innings.

Kay is 1-0 with an 0.00 ERA in two career appearances against Seattle.

Miller went 5 1/3 innings at Houston on Wednesday, giving up two runs on eight hits in a game the Astros won 4-3 in 10 innings. He's 2-0 with a 1.77 ERA in three career starts vs. the White Sox.

--Field Level Media