The manager, who himself is taking a national team to the World Cup for the first time, hoped to name his 23-man final list outright, but injury concerns forced his hand. With players needing rest and preparation matches to be played, he called in several back-up players to fill out the numbers.
Who made Mexico's roster?
There weren't too many surprises on Mexico's squad, other than Osorio naming 28 players instead of the final 23 as he'd hoped.
In goal, it's the trusted trio of Standard Liege's Guillermo Ochoa, coming off winning a Champions League place with the Belgian side, Cruz Azul's Jesus Corona, and Toluca's Alfredo Talavera.
Defense continues to be a concern, but Carlos Salcedo's injury recovery and return to the field for Eintracht Frankfurt has been a boost.
Rafa Marquez is on the list after worries that off-the-field issues would deny the 39-year-old the chance to play at his fifth World Cup.
Hector Moreno is recovered from his injury, but several Mexican center backs weren't so lucky. Tigres center back Hugo Ayala and America's Edson Alvarez, the youngest player in the call-up, are in the team and will be called upon to fill the roles typically played by Nestor Araujo and Diego Reyes.
The left-back spot is of little concern with Miguel Layun fit and Jesus Gallardo ready to be his deputy.
In the midfield, Andres Guardado is coming off an excellent season with Real Betis. He too is recovering from a knock, but Osorio is optimistic about his chances of arriving in Russia fully fit.
It was a fantastic season in Europe for Hector Herrera as well. The Porto midfielder captained his team to a championship. LA Galaxy midfielder Jonathan dos Santos isn't having as good of a year with his club, but is on the roster and hoping to make the World Cup for the first time. His brother, Giovani dos Santos scored in the 2014 tournament but is coming off an injury.
Marco Fabian stood out at that tournament and recovered from his back injury that forced him to miss much of the season with Eintracht Frankfurt to make the list.
After Reyes pulled out with his hamstring issues, Pachuca's Erick Gutierrez, a 22-year-old midfielder was added to the roster. He was the biggest surprise on the provisional roster but has earned his way into the full team.
On the wings there's in-form LAFC attacker Carlos Vela, who is pushing to start at right winger, where Osorio likes to play him with an inverted profile. Porto midfielder Jesus "Tecatito" Corona struggled for consistency with his club this year, but it wasn't long ago that Mexico fans considered him a must-start player - and the talent is still there. Tigres winger Javier Aquino has earned plenty of minutes in the Osorio era and looks to lend experience and strong crossing to the group.
Mexico has plenty of familiar faces up top. The breakout star of the team is Hirving Lozano, who helped PSV to a title in his first season in Europe. Things didn't go as well for Javier "Chicharito" Hernandez at West Ham, but the 29-year-old forward has the talent to lead the line for El Tri. Osorio wants to take three No.9s to Russia, so Benfica forward Raul Jimenez and Club America veteran Oribe Peralta round out the forwards.
Who didn't make Mexico's roster?
Diego Reyes was with El Tri in Russia but couldn't recover from a hamstring injury and had to pull out less than a week before the start of the tournament.
Chivas' Oswaldo Alanis was one of the final players cut from the team. Tigres winger Jurgen Damm and Monterrey midfielder Jesus Molina also missed the final cut.
After excellent campaigns in Liga MX, many were pushing for Chivas attacker Rodolfo Pizarro or Santos Laguna midfielder Jose Juan "Gallito" Vazquez to make the provisional list, but there isn't space for either one.
After an injury during the club season kept him from suiting up for Mexico after his El Tri debut in January, 19-year-old Jonathan Gonzalez headed to the Toulon Tournament for rising stars rather than the World Cup. So too did club teammate Cesar Montes, a center back.
Omar Govea also will look to 2022 after a dispute with his club manager resulted in a dip in playing time in Belgium, and the midfielder failed to impress enough after being called in for the March friendly matches.
While Santos Laguna center back Nestor Araujo actually is on the squad, tendonitis experienced during recovery from a knee injury suffered in a March friendly against Croatia will keep him from making the flight.
Long shots who missed out
A hot start to the Clausura from Club America forward Henry Martin earned him a January call-up, but he cooled and wasn't in the picture.
Victor Guzman had started his push before suffering a season-ending injury with Pachuca. Injuries also vexed Tigres right back Luis "Chaka" Rodriguez, who twice recovered from a muscle injury but didn't see enough of the field in the stretch run of the Clausura to turn Osorio's head.
After calling in fullbacks like Paul Aguilar, Luis Reyes and Adrian Aldrete earlier in his tenure, it looks like Osorio was set with Layun and Salcedo, with none of those players called in this year.
The strong group of goalkeepers made it impossible for up-and-comer Rodolfo Cota or veteran Moises Munoz to edge into the group.
Forward Alan Pulido missed the Gold Cup with an injury and never could bounce back to the level Osorio expected.
Mexico's World Cup 2018 squad in full
Goalkeepers (3): Guillermo Ochoa (Standard), Alfredo Talavera (Toluca), Jesus Corona (Cruz Azul)
Defenders (7): Carlos Salcedo (Eintracht Frankfurt), Diego Reyes (Porto), Hector Moreno (Real Sociedad), Hugo Ayala (Tigres), Edson Alvarez (Club America), Jesus Gallardo (Pumas), Miguel Layun (Sevilla)
Midfielders (6): Rafa Marquez (Atlas), Hector Herrera (Porto), Jonathan dos Santos (LA Galaxy), Andres Guardado (Real Betis), Marco Fabian (Eintracht Frankfurt), Giovani Dos Santos (LA Galaxy)
Forwards (7): Javier "Chicharito" Hernandez (West Ham United), Raul Jimenez (Benfica), Oribe Peralta (Club America), Jesus "Tecatito" Corona (Porto), Carlos Vela (LAFC), Javier Aquino (Tigres), Hirving Lozano (PSV)
Mexico starts its World Cup campaign with a June 17 game against Germany before taking on South Korea on June 23 and closing out group play against Sweden on June 27.