It was only the first day of training camp, but Atlanta United took several steps to shape its roster.

Technical Director Carlos Bocanegra provided several updates as Atlanta United opened camp for its second season on Monday at the team’s training facility in Marietta.

Every player with the exception of newly acquired Ezequiel Barco arrived on Monday. Work is being done on his P1 Visa.

Hector Villalba, a Argentinian midfielder who scored 13 goals and added 11 assists last season, has secured his green card. The move frees up one of the International slots Atlanta United has available on its roster, which must be compliant by March 1.

“One of the cool things about coming to America is ... ‘Tito’ has his green card and can come and go as he pleases and eventually live her if he would like,” Bocanegra said. “It’s a pretty special thing.”

Bocanegra said the team is working to secure green cards for several other players, but declined to say which ones. Last season, the team secured green cards for Chris McCann (Ireland), Kevin Kratz (Germany) and Kenwyne Jones (Trinidad and Tobago).

Each MLS team is given eight spots for International, or non-American, players on its roster. The spots are tradeable between teams.

The team hasn’t released its preseason roster, but it will likely need to secure several more green cards because it is projected to have more players than it will have International slots.

Among the other players occupying International slots are Julian Gressel (Germany), Romario Williams (Jamaica), Leandro Gonzalez Pirez (Argentina), Miguel Almiron (Paraguay) and Josef Martinez (Venezuela).

The team drafted three international players: Jon Gallagher (Ireland), Oliver Shannon (England) and Gordon Wild (Germany), in addition to acquiring Barco (Argentina), Franco Escobar (Argentina) and Jose Hernandez (Venezuela) in the offseason.

Bocanegra said having Atlanta United 2, its USL team that will play at Coolray Field in Lawrenceville, provides an advantage because the senior team can loan International players to the team and those players won’t count against the International slots on the roster. Atlanta United loaned Williams to Charleston, then its affiliate in USL, for an entire season last year, but loans can be for shorter increments.

Continuing with the roster building, Bocanegra said the team is working on adding another player. He declined to say what position, or even if the player coming would help more on offense or defense.

Bocangera did say that defensive midfielder Carlos Carmona is under contract and is expected to stay with Atlanta United for the season. Carmona is reportedly a target of Colo-Colo in his native Chile.

With Carmona, Atlanta United has a glut of talented midfielders in the center of the pitch. The team re-signed Jeff Larentowicz and traded for Darlington Nagbe. Almiron is likely the team’s central attacking midfielder.

Manager Gerardo Martino said he’s not sure how he will be able to get them all on the field, but joked that maybe they will petition MLS to allow them to field 12 or 13 players.

After Scott Donnelly was announced as coach of Atlanta United 2 last week, Bocanegra said the assistant coach will be named this week and the team is close to signing eight to nine players and will look at add three or four more. Preseason starts Feb. 12.

Atlanta United 2 will train in Marietta, sometimes scrimmaging with the senior team.