I don’t think it’s really that outrageous to say that his Leverkusen stint was more impressive than Slot’s at Liverpool. Leverkusen is not a top tier club in the Bundesliga, and yet Xabi built them up from a side sitting in the relegation places to one which went undefeated and won the title - an impressive feat when considering Bayern Munich’s stranglehold on the league.
Obviously, Slot’s Liverpool side was better than Alonso’s Leverkusen side. But Slot inherited his team from Klopp and put together about six months of excellent performances before becoming what we see now - a side struggling to find an identity.
I don’t think the club would sack Slot just because Alonso is available. I think they’d sack Slot because of the team’s performances - and Alonso’s availability would give them an appealing option to consider as a replacement.
