To cover that hypothetical scenario, here is a scouting report on Manolas.
Starting alongside Sokratis Papastathopoulos, Manolas was excellent for Greece during the 2014 FIFA World Cup.
Manolas locked down Costa Rica centre-forward Joel Campbell, winning 100 percent of headed contests, per Squawka.com, during Greece's 5-3 penalty shootout defeat to Los Ticos (the game ended 1-1 after extra time).
Ivory Coast centre-forward Didier Drogba failed to even shoot once, let alone score, which was a testament to how tough Manolas and Sokratis were in Greece's 2-1 win over the African nation.
Manolas cleared the ball four times, made two tackles, intercepted two passes and blocked two shots as Greece kept a clean sheet in a 0-0 draw against Japan.
While Manolas committed an error in Greece's 3-0 defeat to Colombia, he pulled off a last-man tackle and was involved in several plays that ensured that Fernando Santos' team did not lose by a bigger margin.
Throughout the tournament, Manolas proved he can thrive at international level.
- Manolas' clearances per game (6.0) was higher than Italian centre-back Giorgio Chiellini (4.7).
- Manolas' pass completion percentage (87.5) is comparable to German centre-back Mats Hummels (87.2).
- Manolas averaged more headers won per game (3.3) than English centre-back Gary Cahill (3.0).
- Manolas' tackle completion percentage (75, per Squawka.com) was more proficient than Brazilian centre-back David Luiz (46, per Squawka.com).
Doing business with Olympiacos is risky.
Pointing to former Olympiacos player Yaya Toure's success would be confirmation bias.
Fulham were burnt when Konstantinos Mitroglou, a £12 million relegation insurance plan, started one game and made three appearances in the Premier League as the Cottagers dropped down to the Championship last season.
Olympiacos also extracted €20 million from Shakhtar Donetsk for Nery Castillo in 2007. Shakhtar believed they were getting an asset who could be sold for a profit in the next few years. Instead, his career crashed and burned.
Valencia's management team thought they could quell Zlatko Zahovic's fiery nature, but they were wrong.
He lasted only a season after a £5.5 million transfer in 2000, per the Guardian: "Zahovic left Olympiacos in 2000 after criticising the club and joined Benfica, having previously departed Valencia after a spat with coaching staff."
Grigoris Georgatos could not acclimatise to Italy having moved to Inter Milan in 1999, per Simon Kuper at the Observer (h/t the Guardian): "Grigoris Georgatos, the Olympiacos defender, joined Inter Milan a year ago, played rather well, but returned to Greece after one season desperately homesick despite having spent most of his free time in Athens."
The idea of Liverpool signing Manolas has holes.
He does not have an extensive background playing in an elite European league; it would be a prisoner-of-the-moment decision.
Four years ago, then-23-year-old South African centre-back Bongani Khumalo showed great potential and was named as an outstanding player at the 2010 World Cup, per FIFA.com.
Khumalo has never made a Premier League start, despite being on the books of Tottenham Hotspur since 2011.
Theoretically speaking, let's say the Liverpool front office are interested in Manolas.
They need to consider Olympiacos' extensive track record of selling flops and Manolas lacking a body of work in a top European league.
But going by the eye test, he is a defender with elite upside.
He is strong in the air, tackles confidently and is a passing outlet from the back.
Manolas would be an upgrade over Liverpool backup centre-back Kolo Toure.
Statistics via WhoScored.com