Ajax revamped their central defence in the summer. Ko Itakura and Josip Sutalo left the club to join Borussia Mönchengladbach and Lazio, respectively. Ahmetcan Kaplan, who was on loan at NEC Nijmegen last season, joined the club on a permanent transfer this summer.

To strengthen their options in central defence, Ajax signed Daley Blind on a free transfer following the expiry of his contract at Girona. The Amsterdammers also signed Thilo Kehrer from AS Monaco on loan, and Dies Janse returned to the club after a productive loan spell last season at FC Groningen.

Baas and Aaron Bouwman have started the majority of games for Ajax this season in central defence, but Kehrer and Janse have also made a positive impression. Blind has only just returned to action after spending over two months on the sidelines due to an injury.

While Baas has started more games than Janse in the left centre-back position, various reports in the summer claimed that Ajax were prepared to sell Baas as they see more long-term potential in Janse. 

Baas attracted interest from Porto and Eintracht Frankfurt in the summer but stayed in Amsterdam after a transfer failed to materialise. He could leave the club in the winter transfer window, though, with FC Barcelona reportedly keen on his signature.

According to SPORT, Barcelona want to strengthen their central defence, and Baas is on their shortlist. Baas is highly regarded by the reigning La Liga champions, and they greatly value his ability to play as a left-back.

Barcelona are looking for a centre-back that is technically gifted, quick and a player who can adapt to the demands of Hansi Flick's system. In addition to Baas, they are also interested in Vitor Reis from Manchester City, Arthur Dias from Athletico Paranaense and Ruud Nijstad from FC Twente.

The Spanish giants are also in the market for a more experienced centre-back, and former Ajax defender Lisandro Martinez, who currently plays for Manchester United, is on their shortlist.

Baas is a very good centre-back and is an important player for Michel Sanchez, but Ajax should sell him if a suitable offer arrives.

Janse has impressed in the games he has played this season and is a very well-rounded centre-back. He is ready to start games regularly, and he and Bouwman complement each other very nicely.

Ajax also have Blind, who is extremely experienced and still possesses immense quality, especially on the ball. He and Janse would provide Michel with very good depth in the centre-back position in the event Baas does indeed leave.

Because Ajax would not need to sign a centre-back to replace Baas, the money earned from his departure could be used to strengthen the squad in other areas.