Chelsea fans were delighted after their academy graduate Tammy Abraham yet again showed his class for AS Roma in their UEFA Europa Conference League tie against CSKA Sofia.Chelsea fans took to Twitter to stamp their approval for Tammy Abraham's outstanding start to life in Italy under former manager Jose Mourinho. Here are some of the best tweets:Beekay Baltu@Gee_Uneet@europacnfleague @ASRomaEN @OfficialASRoma @tammyabraham I am really happy for himI hope he keeps getting better and better Sad to admit leaving chelsea was a smart move for him10:36 AM · Sep 17, 20212@europacnfleague @ASRomaEN @OfficialASRoma @tammyabraham I am really happy for himI hope he keeps getting better and better Sad to admit leaving chelsea was a smart move for himFlair ⚡️@FlairCFCRemember when Tammy Abraham scored a hat trick past Rui Patricio 2 years ago? Who’d of thought that two years after that they’d both be playing for the same team in Italy 😭1:46 AM · Sep 13, 20211772Remember when Tammy Abraham scored a hat trick past Rui Patricio 2 years ago? Who’d of thought that two years after that they’d both be playing for the same team in Italy 😭 https://t.co/mY3L6HmukOKellz@KellieKoroma2Happy for @tammyabraham fr see you back @ChelseaFC in ah few years2:57 AM · Sep 17, 2021Happy for @tammyabraham fr see you back @ChelseaFC in ah few yearsPolo @MrPolo_Tammy Abraham is flourishing under Jose man. I’m so happy for him. Shomurodov looks deadly too.12:53 PM · Sep 17, 2021Tammy Abraham is flourishing under Jose man. I’m so happy for him. Shomurodov looks deadly too.CFC Jafar ⭐️⭐️🏆@cfc_jafar@HajirFT @tammyabraham Jose will make us activate his buy-back clause in 3 years. Can't wait him at chelsea again5:58 AM · Sep 16, 20218@HajirFT @tammyabraham Jose will make us activate his buy-back clause in 3 years. Can't wait him at chelsea againyams@noiceyamsTammy Abraham is so so good playing outside of Chelsea, Im sure Chelsea is buying him back LOL6:32 AM · Sep 15, 2021Tammy Abraham is so so good playing outside of Chelsea, Im sure Chelsea is buying him back LOLThe reason behind Chelsea fans' excitement surrounding Abraham's good form is that the Blues have inserted a buy-back clause in his deal with AS Roma. According to the reports, the buy-back clause is of around £68 million. However, it will only get activated in the summer of 2023.Tammy Abraham was one of the main players at Chelsea under the management of Frank Lampard. However, the 23-year-old forward had fallen down the pecking order since the arrival of Thomas Tuchel at Stamford Bridge. The Blues decided to sell Abraham this summer after signing Romelu Lukaku from Inter Milan for a club-record £97.5 million.As things stand, Abraham is flourishing under former Chelsea manager Jose Mourinho at AS Roma. The English forward has so far contributed two goals and two assists in all competitions as AS Roma sit top of the Serie A table with nine points from their first three games.Not all Chelsea outgoings have a buy-back clause like Tammy AbrahamNot every Chelsea outgoing has a buy-back clause in their contract. According to Italian journalist Fabrizio Romano, Fikayo Tomori does not have a buy-back clause in the deal which saw him join Serie A giants AC Milan on a permanent basis for a fee of around €29 million.The former Chelsea defender is now considered "untouchable" at AC Milan and it would be difficult for the Blues to sign him back if Tomori develops exceptionally well in Italy.Fabrizio Romano@FabrizioRomanoUnlike what they did for Tammy Abraham deal, Chelsea have not included any buy back clause for Fikayo Tomori. AC Milan signed him paying full €29m buy option after 6 months loan. 🔴 #ACMilanTomori is now considered ‘untouchable’ - AC Milan are loving him and his impact.5:21 AM · Sep 16, 2021319461964Unlike what they did for Tammy Abraham deal, Chelsea have not included any buy back clause for Fikayo Tomori. AC Milan signed him paying full €29m buy option after 6 months loan. 🔴 #ACMilanTomori is now considered ‘untouchable’ - AC Milan are loving him and his impact.The likes of Tammy Abraham and Fikayo Tomori have proved that Chelsea youngsters have a chance to prove their worth abroad. Chelsea possess some of the best young talents in England but rarely give opportunities to their youngsters. Instead, the club generally spends big on superstar players.However, some talented Chelsea teenagers might take inspiration from Abraham and Tomori and move away from Stamford Bridge to kickstart their careers.You may also like: Paul Merson predictions for Tottenham vs Chelsea and other Premier League GW 5 fixtures