Alonso is expected to use a back three at Stamford Bridge, a system Lacroix already knows well. His pace, physical presence and ability to defend space make him a natural fit for a structure that asks the outside centre-backs to step forward and cover wide areas.
Lacroix’s profile also offers Chelsea greater tactical flexibility. He can operate in a conventional back four, but his experience in a back three could allow Alonso to switch formations without changing personnel.
Reports suggest the player would welcome a move across London. That could help Chelsea, although it will not automatically reduce Palace’s negotiating position.
Palace’s valuation has reportedly risen after recent Premier League deals for centre-backs, including Tottenham’s move for Jan Paul van Hecke. Lacroix also has three years remaining on his contract and has become vice-captain since arriving from Wolfsburg.
His importance is reflected in Palace’s recent success. He played a key role during a period in which the club won the FA Cup, Community Shield and UEFA Conference League - the first major trophies in their history.
The club are reportedly exploring Chrislain Matsima as a possible replacement, but that does not mean a sale is inevitable. Palace are also preparing for European football and may prefer to retain their defensive leader.
Chelsea’s interest is tied to a wider squad reshaping. Axel Disasi and Trevoh Chalobah are reportedly available, while Chalobah has been linked with Como.
That creates a clear sequence for Chelsea: move defenders out, then decide whether Lacroix justifies a fee above £50m. Palace’s firm stance could force a choice between paying the premium or pursuing a cheaper alternative.
The next phase of negotiations will determine whether Lacroix becomes Alonso’s first defensive priority or Palace’s latest example of selling only on their terms.