Manchester City kick off their Premier League title defense with a match against Tottenham Hotspur on 15th August. It will be the first time Pep Guardiola takes his team to the pitch without the presence of a recognized striker in his locker room.While the issue could be addressed before the transfer window shuts on August 31st, there has yet to be any conclusive evidence on the same.Manchester City's Premier League title defense could be toughThe Premier League is set to become even more competitive this time around with the addition of some world-class stars. The likes of Raphael Varane, Jadon Sancho and Romelu Lukaku will all add to the league's glory.Even Tottenham, under their new manager Nuno Espírito Santo are making headway in bringing in top-quality players to strengthen their squad. Hence, the Premier League title defense won't be straightforward for Guardiola and his men.So ahead of the big weekend, let's discuss five of the biggest hurdles that stand in Manchester City's way as they begin their Premier League title defense.#5 Absence of a recognised strikerEngland Training Camp - Euro 2020Following the departure of Sergio Aguero in the summer, Manchester City are without an out-and-out striker. While Gabriel Jesus is still at Guardiola's disposal, the Spaniard prefers to play him on the left side of the pitch rather than up front.Manchester City recently broke the Premier League transfer record with the €118m signing of Jack Grealish from Aston Villa. Despite that, their attack looked toothless in the 1-0 loss against Leicester City in the Community Shield last weekend.Now Guardiola desperately needs to find a player who can fill the void at the top. While Harry Kane has been linked with yet another record-breaking move, things look quiet on that front. The player in fact recently claimed that there is no truth to reports about him intentionally missing training.🚨 NEW: Harry Kane is set for a £160m transfer to Man City after Daniel Levy agreed to let the striker leave. Kane is understood to have shaken hands on a £400,000-a-week deal with Man City. [The Sun] pic.twitter.com/VFEePlbb3m— The Spurs Web ⚪️ (@thespursweb) July 22, 2021Tottenham manager Nuno Espirito Santo has also confirmed that the England striker could be involved against Manchester City on Sunday.Failure to get their hands on a recognized striker could prove to be detrimental in the race to retain the Premier League title.#4 An anticipated slow start to the seasonManchester City FC Training Session and Press Conference - UEFA Champions League Final 2021Manchester City had as many as 14 players on international duty during the European championships, with another two Gabriel Jesus and Ederson plying their trade in the Copa America.The Euro 2020 journey will've only helped our English lads! 💪More post-match thoughts from Pep ⬇️🔷 #ManCity | https://t.co/axa0klD5re— Manchester City (@ManCity) August 8, 2021Those players were given additional time off and it was not until Monday that Guardiola had his entire squad at his disposal barring Aymeric Laporte, who is in quarantine.Manchester City had as many as nine of their starters, including the injured Kevin De Bruyne and Phil Foden, missing for the game against Leicester City.The manager admitted that just like the previous season, his team will arrive "late". So the results could be a bit flat at the start as they were last time around.Although Guardiola is confident that his team will bounce back like history suggests, they could find themselves well behind the pack with a slow start in the Premier League.