The Cubs made a roster move ahead of their series opener on Monday in Pittsburgh.

Right-handed pitcher Adrian Sampson was optioned to Triple-A Iowa and the team recalled outfielder Nelson Velázquez. The team needed to trim the number of pitchers on their roster from 14 to 13 by today, so Sampson was the pitcher sent down. Major League Baseball’s 13-pitcher limit went into effect for all teams on Monday. The rule was supposed to be implemented for the entire season but after the shortened Spring Training, the league decided to have a grace period until June 20.

Sampson was stellar Sunday afternoon against the Braves, pitching 4.2 scoreless innings in relief of Kyle Hendricks and throwing 56 pitches. His option was a difficult move, coming off a strong outing, but one that made sense in the bigger scheme of the roster as it stands.

“[He] allows us to reset that bullpen with probably one of the better performances I’ve seen him have and one of the better performances out of our bullpen,” Ross told reporters in Pittsburgh. “But he’s probably down for three days and we can’t use him and we’re cutting down a pitcher. At this moment in time we cannot afford to be short with still no off days coming up.”

The Cubs’ rotation — even with three injuries to it ­— is filled out with Hendricks, Justin Steele, Keegan Thompson, Matt Swarmer and Monday’s starter, top prospect Caleb Kilian. The Cubs also have a multi-inning-relief option in Alec Mills, who can also slide into the rotation if needed and he’s out of minor league options. That all pointed to Sampson as the Cubs’ choice to send down.

Sampson will provide the Cubs with depth — he can be recalled and fill in in the rotation or serve as a multi-inning reliever. At Iowa, he’ll be used regularly and can be ready if the team needs him.

“The conversation with Sampson was extremely difficult,” Ross said. “Unfortunately, that’s part of this game and probably one of the worst messages you have to deliver. He’ll continue to establish himself as a big leaguer and yesterday was a really good step in that direction.”

Velázquez spent 3 days with the major league team earlier this month, but he made sure to make the most of that time. He picked the brains of veterans like Willson Contreras and Jason Heyward, who stressed the importance of timing. At Iowa, he focused on that timing and his two-strike approach and hopes he can use that in this stint back with the Cubs.

“They explained to me, the most important thing to hit is to be on time,” Velázquez said. “If you’re on time, you will be able to adjust your swing, no matter what pitch it is.”