D.C. United left several roster slots open in anticipation of signing additional players once the season began. And now, one match into the new campaign, the MLS club is preparing to make two moves.

Costa Rican defender Joseph Mora and Jamaican forward Dane Kelly, the all-time leading scorer in the second-division United Soccer League, joined the team at Tuesday’s training session and seem certain to sign soon.

Their arrival was unrelated to the opening-day result, a 1-1 draw at Orlando City on Saturday. United General Manager Dave Kasper last week had hinted at new players coming soon and Friday traded with Portland for an international roster slot. (Mora is a foreign player, but Kelly has permanent U.S. residency and doesn’t count against the limit.)

United is in the process of purchasing Mora, 25, from Costa Rican club Saprissa. Visa issues will probably prevent him from playing for a few weeks but, once he is eligible, Mora is likely to start at left back. Taylor Kemp is sidelined indefinitely after suffering a setback in his recovery from hernia surgery last fall. Oniel Fisher, a Jamaican acquired from Seattle last month, started there Saturday.

“His one-on-one defending is high-quality. Technically, he is sound,” Coach Ben Olsen said of Mora. “Now it’s a matter of getting him up to speed with how we want him to defend and attack. That’s going to take a little bit of time, but he’s an intelligent kid, and I think that process will move pretty quickly.”

Kelly, 27, starred for the Charleston Battery (2011-15) and suburban Kansas City’s Swope Park Rangers (2016) before joining Reno 1868 last year. He scored a league-high 18 goals in 28 matches, the second-highest output in league history, and was named USL most valuable player. He reportedly was close to signing with an Indian club late last summer.

Kelly made his Jamaican national team debut in September against Canada, then scored in January against South Korea.

Darren Mattocks, a fellow Jamaican, is likely to remain Olsen’s primary striker, with Patrick Mullins in reserve.

“He has been very good in the USL,” Olsen said of Kelly. “Just adds some depth and competition up top.”

With Kelly’s acquisition imminent, Bolivian attacker Bruno Miranda, 20, is slated to join second-tier Richmond soon. He will shuttle between United and the Kickers but, with few if any opportunities to play in MLS matches, he will receive regular minutes with Richmond.

United visits Atlanta on Sunday.