Barcelona president Josep Maria Bartomeu is one of the most criticised football chiefs in world football at the moment. The Catalan took over the reins of Sandro Rosell in January 2014 after the former president stepped down amidst allegations of tax fraud during the infamous Neymar case.Since his appointment, Barcelona have established a stronghold on LaLiga Santander, winning four of the six LaLiga titles available to them in that period, along with as many Copas del Rey. However, their failures, and pretty significant ones at that, lie elsewhere.Barcelona's embarrassing eliminations from Europe time and again have raised questions over the club's UEFA Champions League credentials. More so, their poor squad planning, questionable decisions in the transfer market, and reckless spending have all been issues that have plagued the Blaugrana.🗣[@LuisOmarTapia] | Barça Legend Stoitchkov spoke to Bartomeu about Davies months before Bayern came on board. His response was, "he is Canadian no thanks." pic.twitter.com/MEzeaZizl7— BarçaTimes (@BarcaTimes) August 15, 2020The 8-2 defeat to Bayern Munich has all but ensured that the club will go through an overhaul to compete for top honours again after suffering their first trophyless season since 2008. That would effectively mean disposing of the ample amount of deadwood in the squad and replacing them with young blood — something that Barcelona have failed to do over the last few years.Here, we take a look at the five worst signings made under the leadership of Barcelona's 40th president, Josep Maria Bartomeu.#5 Ousmane Dembele | €138mA rare sight of Ousmane Dembele in action during the 2019/20 campaignIt would be harsh to blame Bartomeu, or in fact, any football executive for the on-field failures of any given signing they make. However, Ousmane Dembele's move has brought next to nothing to this Barcelona side, and has spent more time on the treatment table than he has on the pitch.The outrageously talented winger was once seen as a player who could go on to emulate some of the greatest players to grace the game and create a legacy at the Nou Camp. However, Dembele's discipline has continuously been in question, be it in the form of turning up late to training, or looking after his physical well-being.1 - Ousmane Dembélé is the first French player to score a brace for Barcelona in La Liga since Thierry Henry vs Real Madrid in May 2009. Gourmet. pic.twitter.com/aMzvdqTViq— OptaJose (@OptaJose) May 9, 2018The 23-year-old has missed just over 80 games (!) since he arrived at the club in the summer of 2017 in the wake of Neymar's departure from the Nou Camp. In terms of days missed due to injury, Dembele tallies at over 500 days spent on the sidelines. The Frenchman has managed just 35 LaLiga Santander starts in his three-year stay at the club.Barcelona are reportedly looking for buyers to offload one of their most expensive players this summer. While Dembele has an ample amount of time left to kickstart his career elsewhere, it's safe to say that Borussia Dortmund — his former club — emerged as the only winners from his move to the Nou Camp. His hefty price-tag and inability to offload him (so far) have made it a disappointing signing.#4 Samuel Umtiti | €25mUmtiti's steady decline has forced Barcelona to look for suitorsNot too many people were aware of Samuel Umtiti's talent until Barcelona shelled out €25m on the Frenchman just two days after making his competitive debut for France. Almost immediately after his signing, the world was suddenly in awe of the composed left-footed defender at the heart of UEFA Euro 2016 finalists France's defence.After a respectable couple of seasons at the Nou Camp and a successful FIFA World Cup campaign where Umtiti was a staple in the first XI, things quickly unravelled for the talented centre-half. In truth, ever since June 3, 2018 — the day Barcelona rewarded Umtiti with a contract extension — things have never been the same for the Frenchman.107 - Samuel Umtiti has completed 100% of his passes v Iceland tonight (107/107), a record for a France player over the last 10 years. Watchmaker. pic.twitter.com/up3rTAgJal— Optajean (@OptaJean) March 25, 2019Since the date mentioned above, Umtiti has gone on to miss a staggering 45 games in two years due to recurring injury issues. Even when the 26-year-old took to the pitch, he looked a pale shadow of the uber-talented defender they signed from Olympique Lyon.Much like Dembele, the reasons for Umtiti's decline and an influx of injury woes remain a mystery, and Barcelona are actively trying to find him a new club at the earliest juncture possible. The World Cup winner went from being tipped to be the heir to Javier Mascherano's Nou Camp throne to being offered to clubs such as West Ham and Everton.Also read: Barcelona shortlist three managers to replace Quique Setien