CINCINNATI -- Twice in two days, the Reds will use a starting pitcher making his Major League debut. The club announced on Monday that right-hander Riley O'Brien will be called up from Triple-A Louisville to face the White Sox in their two-game series opener on Tuesday at Guaranteed Rate Field.

Cincinnati summoned lefty Reiver Sanmartin from Louisville to replace the injured Wade Miley for Monday¡¯s game vs. the Pirates at Great American Ball Park. O¡¯Brien was needed to replace Luis Castillo, who was placed on the family emergency leave list.

¡°Another talented pitcher. He's had a nice season,¡± Reds manager David Bell said of the 26-year-old O'Brien. ¡°He's been on the radar for a long time. Just to see him in Cincinnati here and get a start, it's great for him, but also for us to get to see him at this level. Another guy that we'll get to watch and observe and see how he does here. I'm anxious to see him here [Tuesday].¡±

O¡¯Brien, the club's No. 24 prospect, joined the organization in an Aug. 28, 2020, trade with the Rays in exchange for left-handed pitcher Cody Reed. In 23 games (22 starts) for Louisville, O'Brien was 7-7 with a 4.55 ERA and a 1.31 WHIP.

According to the Elias Sports Bureau, it¡¯s just the fourth time in modern history -- and the first since 2017 -- that the Reds had starting pitchers make their big league debuts in consecutive games. In 2017, Rookie Davis faced the Phillies on April 6 and Amir Garrett started on April 7 against the Cardinals. Cincinnati also had back-to-back debuting starters in 1902 and '47.

Rotation rest of way
Following O¡¯Brien, Sonny Gray will start on Wednesday vs. the White Sox. There is an off-day on Thursday. Castillo¡¯s next start was pushed back to Friday at Pittsburgh, followed by Tyler Mahle on Saturday.

The starter for Sunday¡¯s regular-season finale is listed as TBD.

Farmer¡¯s special grand slam
During Sunday¡¯s 9-2 victory over the Nationals, shortstop Kyle Farmer put the game away in the sixth inning with the first grand slam of his career. In an at-bat where he was given only breaking balls, Farmer hit a 2-2 slider from Ryne Harper and drove it into the left-field seats to make it a 7-1 game.

While talking after the game with reporters on Zoom, Farmer was holding his newborn son, McCoy James Farmer, who slept in his arms. It was the first time McCoy had been to the ballpark.

¡°It's amazing having him here, Courtney being here, and hitting a grand slam, it's awesome,¡± Farmer said. ¡°I think you dream about this kind of stuff and here it is. It's pretty awesome.¡±

It¡¯s been a nice season for Farmer, who became a regular in the lineup for the first time in his career. He entered Monday slashing .262/.315/.419 with 16 home runs and 63 RBIs in 144 games.

Farmer competed for the shortstop job in Spring Training, but he lost out to Eugenio Su¨¢rez. When Su¨¢rez struggled and moved back to third base, Farmer assumed the job at shortstop and proved highly dependable.

¡°I think it all starts with keeping a positive attitude and waiting for your opportunity and making the most of it and just keep being positive and staying with it and trusting the process,¡± Farmer said. ¡°If I was a negative person, I'd probably be out of this game by now with what I've had to go through. Baseball's an up-and-down game, and you never know when you're going to get your shot and you just have to keep going.¡±