KANSAS CITY -- There suddenly is greater responsibility on the shoulders of Royals left-hander Mike Montgomery.

The Royals¡¯ rotation, thin even before Spring Training started, has gotten thinner during Summer Camp. Right-hander Brad Keller, last year¡¯s Opening Day starter, just returned from the injured list [COVID-19] last Friday.

And right-hander Jakob Junis, projected to be the No. 3 starter, went on the IL on Monday. Junis missed the first part of Summer Camp after testing positive for COVID-19, and he will require extra time to get ready for his regular-season debut.

That leaves left-hander Danny Duffy and Montgomery as the only two expected starters in 2020 who are ready to go. Montgomery¡¯s final Summer Camp test came on Monday night at Kauffman Stadium in a 6-3 exhibition loss against the Astros.

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¡°Me and Danny talked about it,¡± Montgomery said. ¡°We definitely have to do our part. We have to eat some innings. Losing those two guys [Keller and Junis] is big. Everyone, including myself, will have to pick up the slack.¡±

Montgomery had his positive moments, at one point retiring eight of nine hitters. He went 3 2/3 innings overall, giving up four hits and five runs, though only one earned run.

¡°I definitely had a little more nerves when you face a team in a different uniform,¡± Montgomery said. ¡°First couple of innings, I was just trying to slow it down and get my delivery down.

¡°I thought I made some good pitches, but I just couldn¡¯t get that last out. All in all, I think it was OK.¡±

Montgomery would have had a 1-2-3 fourth inning had it not been for a fielding error when third baseman Maikel Franco threw a bit high to first on a grounder from Yuli Gurriel, and first baseman Ryan McBroom couldn¡¯t bring it down.

Montgomery then allowed two-run home runs to Josh Reddick and former Royals catcher Mart¨ªn Maldonado.

¡°[Montgomery] was just getting a feel for the mound early on,¡± manager Mike Matheny said. ¡°I thought he did a nice job after the start. Unfortunately in the fourth, we had a play we usually make that didn¡¯t get made, and it turns into four runs.

¡°But he also has to be able to help out his defense there because they are going to make plays. But his strikeout pitch, his changeup, looked really good.¡±

Reddick hit a sinker that was middle-in. Maldonado jumped a middle-in cutter.

¡°Definitely mistakes,¡± Montgomery said. ¡°I fell behind both of those guys. Ramifications of this game are different than regular season. I was just trying to throw as many fastballs as I could. That¡¯s something I might not do in the regular season.¡±