To cover that hypothetical, here is a scouting report on the 23-year-old Tunisian international.
Khazri is a 6'0", 168-pound footballer, who can start on either flank as a wide attacking midfielder in a 4-2-3-1 and has filled in as a left wing-back in a 3-5-2.
Lallana's ability to interchange across midfield is a trait Khazri can emulate.
Khazri is a tricky proposition for opposing defenders and a skillful entertainer, as evident when he nutmegged Evian Thonon Gaillard substitute Nadjib Baouia and delivered a rabona cross.
What makes Khazri lethal is his long-range shooting.
He scored a splendid inswinging shot against Lyon.
Khazri flicked the ball up to evade Lille centre-back Marko Basa and hit a blistering instep drive past Lille goalkeeper Steeve Elana.
Khazri caught out Reims goalkeeper Kossi Agassa and Paris Saint-Germain goalkeeper Salvatore Sirigu, two of Ligue 1's best shot-stoppers, with audacious free-kicks.
Khazri displayed his strength when he bounced off Montpellier centre-back Daniel Congre's challenge and slotted the ball past Montpellier goalkeeper Geoffrey Jourdren.
You see a lot of Ricardo Quaresma in Khazri, who was given the keys to Bastia's attack.
What made Quaresma a sensation was having the green light and creative freedom at Porto.
Inevitably, he needed a team to run through him, and he did not develop as a team-first player.
He was more interested in making the highlight-reel play than the right play.
He was a square peg in a round hole at Inter Milan, despite then-Inter manager and compatriot Jose Mourinho pushing then-owner Massimo Moratti to buy Quaresma.
"We don't need Quaresma," Moratti said in 2008, per Nadia Carminati at Sky Sports. "I don't think Quaresma will arrive."
Three days later, Moratti signed Quaresma for €18.6/£15.1 million.
Quaresma later revealed signing for Inter was a big-career mistake.
"As soon as I arrived in [Inter] Milan, it was made clear to me that I was only signed because Mourinho wanted me," Quaresma said in 2010, per Publico (h/t Football Italia). "It would've been better if I had closed my eyes and only woken up now."
Khazri plays with a devil-may-care attitude and is prone to inconsistent spells.
He endured a 15-game run without a goal or an assist in Ligue 1.
Khazri has world-class technique, yet conceded possession 23.4 percent of the time trying to pass.
He is a volume shooter, who has an inefficient shooting accuracy percentage (41), per Squawka.com.
Is Khazri a big fish in a small pond like Quaresma?
|(League Only)||Adam Lallana||Wahbi Khazri|
|Key Passes Per Game||1.9||1.3|
Khazri's statistics are in the ballpark of Lallana, who is not value-for-money at £25 million, per John Percy at the Telegraph.
Bastia have a history of underselling world-class prospects.
- Michael Essien to Lyon in 2003 for €7.8/£6.3 million.
- Florian Thauvin to Lille in 2013 for €3.5/£2.8 million.
- Alex Song to Arsenal in 2006 for €1.2/£1 million.
Khazri possesses world-class ability.
He would be a more economically efficient signing than Lallana for Liverpool.
Statistics via WhoScored.com.