The Gabon team arrived in Bangkok yesterday ahead of their first match against Thailand in the King's Cup tomorrow.
Gabon coach Jose Antonio Camacho is in town with 26 players minus their striker Pierre-Emerick Aubameyang of English Premier League club Arsenal.
However, Gabon and Football Association of Thailand officials said the former forward of Bundesliga club Borussia Dortmund will arrive today.
Gabon's other players include EPL stars Mario Lemina of Southampton and Didier Ndong of Watford.
On the opening day of the four-team tournament at Rajamangala National Stadium, Slovakia take on the United Arab Emirates at 4.30pm and defending champions Thailand meet Gabon at 7.30pm.
The winners will meet in the final and the losers play in the third-place play-off on Sunday.
All matches will be televised live on Thai Rath TV.
Meanwhile, Thailand midfielder Chanathip Songkrasin, who is playing for Japanese club Consadole Sapporo, arrived in Bangkok on Monday night and began training with the team yesterday.
The diminutive playmaker said: "I am very happy to come back and play for the national team. I am also happy to see my teammates. I feel a bit exhausted but that is not a problem for me because I am a professional."
He said he was in confident mood after scoring the winner for Sapporo in the Japanese league at the weekend.
Asked about Thailand's match against Gabon, the 24-year-old star said: "Admittedly, I know only Aubameyang. I know that they are a strong team and have many good players. They are ranked higher than us in the Fifa rankings.
"We have to prove ourselves against a higher-ranked team by beating them."
He added: "It is a great honour to play for Thailand. Our target is to win the title but the most important thing for me is that we must play well in every match."
Serb Milovan Rajevac helped Thailand win the King's Cup last year for his first silverware as coach of the War Elephants and is hoping to lift the coveted trophy for a second time.
Slovakia arrived in Bangkok on Monday night without their midfielder Marek Hamsik of Napoli.
Slovakia coach Jan Kozak said Hamsik was forced to pull out of the squad after getting injured during Napoli's match against Genoa in the Italian league on Sunday.
Hamsik said he was sorry for being unable to travel to Thailand. "I wanted to be part of the team. The tournament is undoubtedly good and played in an interesting destination,'' he said.
Kozak said: "That happens. He was looking forward to joining the team and teammates were looking forward to him joining the team. But then there was that injury."