Barcelona suffered a trophy-less season after losing the La Liga title to Real Madrid and also crashing out of the Champions League following a humiliating 8-2 defeat to Bayern Munich.
"Woolston, a goalkeeper formerly with Newcastle United, appeared in the final two Premier League 2 matches of last season, while centre-back Ercolani has been at the club since 2016. United Under-23s keeper Paul Woolston.
He also explained why midfielder, Ross Barkley, who is the club's spot-kick specialist for this season, did not take penalty for Chelsea during the encounter against Grimsby.
The Argentine's contract at the Camp Nou will end at the end of next season, but reports from Spain say the 33-year-old is set to put pen to paper for him to remain at the club until 2023.
The publication also revealed that Chelsea have produced a number young talents and coaches with the likes of Celtic boss Brendan Rodgers and Frank Lampard's No2 at Derby, Jody Morris, both excelling at the top level.
"While some will inevitably move on, the Under-23s welcome the older members of theAcademy group, who step up to Premier League 2 football. An intake of first-year scholars then replaces them in the Under-18s.