During Manchester City's offseason of heavy spending, Pep Guardiola prioritized improving his midfield and wide areas rather than upgrading the team's defensive unit.
John Stones, an upcoming center back with lots of potential but still much to learn, was the only defender to arrive at Etihad Stadium ahead of the new season despite City's aging collection of full backs and the worrying state of his central defense.
Guardiola might be regretting it now.
Undermined by a porous back line that has kept only two clean sheets in 15 games, City is stuttering as it tries to keep pace with Chelsea near the halfway stage of the Premier League campaign.
City is in fourth place — seven points behind Chelsea — after winning three of its last nine league games, and four of its last 14 games in all competitions. On Saturday, Guardiola's team conceded two goals in the first four minutes and was beaten 4-2 by previously out-of-form Leicester.
The 10-match winning run to open the season seems a distant memory now for City. But even during that period, when Guardiola was being widely hailed for his apparently seamless transition to the English game, concerns were being raised about the team's defense and what the coach was asking of it.
Bacary Sagna, Pablo Zabaleta, Gael Clichy and Aleksandar Kolarov are City's full backs. They are all in their 30s and have been given new tasks under Guardiola, such as playing as center backs in a back three or tucking into central midfield when City attacks to free up space for wingers and be in good positions for an opposition counterattack.
Meanwhile, center backs Stones, Nicolas Otamendi and — when fit — Vincent Kompany are being asked to bring the ball out from the back and start attacks. They are playing in front of a ball-playing goalkeeper, Claudio Bravo, who rarely kicks it long and often takes risks with his passing and build-up play.
It seems like Guardiola hasn't got the defenders to carry out what he wants. The defense is looking exposed and error-prone, and City is conceding sloppy goals that are overshadowing the team's attractive passing game. Guardiola frequently changes from a four-man defense to three at the back, which doesn't appear to be helping, either.
"Always I try to control the games so that we concede few goals," Guardiola said in reference to his time in charge of Barcelona and Bayern Munich, who mostly had strong defensive records. "Here I cannot do that and I have to analyze why."
After the loss to Leicester, Guardiola appeared to dismiss the importance of tackling — "What's tackles?" he said, "... we are not going to win or lose for the tackles" — and suggested he would continue playing the same style.
"Of course here in the Premier League, there are some special things but the pitch is the same, it's 11 vs. 11, so I have to control the little differences between the other leagues. But (my) idea, I think, is good; it will be good."
Not helping City's defense is the fact that when it's breached, Bravo isn't proving as able a shot-stopper as the goalkeeper he replaced, Joe Hart. Bravo doesn't have an imposing presence when strikers bear down on goal and was easily beaten by low shots in the 3-1 loss to Chelsea and the loss to Leicester.
Next up for City is Watford at home on Wednesday, part of a full round of midweek matches in the Premier League. Who knows what the make-up of City's defense will be, and whether Guardiola will play with three defenders or four? At least he has Otamendi back from suspension.
SUNDERLAND vs. CHELSEA
Protecting a three-point lead, Chelsea will be looking for a 10th straight win in the match between first and last in the league.
It's the fifth time that Chelsea has won at least nine straight Premier League games. Five more wins and the leaders will match the Premier League record of consecutive wins, held by Arsenal from 2002.
CRYSTAL PALACE vs. MANCHESTER UNITED
Just when Henrikh Mkhitaryan was looking like a sure starter at United after a slow start at Old Trafford, the playmaker got injured and will have to fight for his place again.
Mkhitaryan scored in United's 1-0 win at Tottenham, but hurt his ankle late in the match and was carried off on a stretcher. He is expected to be out for about two weeks.