Chelsea are reportedly monitoring Porto goalkeeper Diogo Costa as Xabi Alonso weighs up an early test of the club’s No.1 position.
According to The Mirror, relayed by Sky Sports, Chelsea are keeping tabs on the Portugal international as Alonso looks at the goalkeeping department.
The report says Porto value Costa at around £51million, which would make any move a serious statement rather than a low-risk squad addition.
That immediately catches attention at Stamford Bridge.
Chelsea already have Robert Sanchez and Filip Jorgensen in the squad, but Alonso’s arrival was always likely to sharpen the assessment of the team’s spine.
ReadChelsea’s recent transfer update around Cucurella, Adam Wharton and Morgan Rogers already highlighted goalkeeper as one area of concern.
🇵🇹 Chelsea and Xabi Alonso are eyeing up a move for Portuguese goalkeeper Diogo Costa, who has long been a Manchester United transfer target, with a €60m release clause. (via @MirrorFootball) pic.twitter.com/rGOHKz51lP
— ChelsTransfer (@ChelsTransfer) June 17, 2026
Alonso Faces A Clear No.1 Decision
Costa would not arrive as a punt.
He captains Porto, starts regularly for Portugal and ranks among Europe’s more established ball-playing goalkeepers.
That profile matters because modern managers do not judge goalkeepers only on saves. They want calm build-up play, pressure management and authority behind the back line.
Alonso will know that quickly.
After Chelsea finished 10th last season, he has little room for sentiment if he decides the team needs a different profile in goal.
ReadChelsea has already looked at why Mike Penders could challenge Robert Sanchez, but Costa would take that debate onto a different level.
For now, this remains one to watch rather than one to expect.
But if Chelsea are genuinely prepared to shop in the elite goalkeeper bracket, Alonso’s first summer could get serious very quickly.