Gašić joined the club for the 2013–14 winter break off-season. He was given a place in the protocol several times as a reserve player. He was given a chance before the end of season, making 3 league caps with 2 starts.[12] Playing with Mladost Lučani, he won the Serbian First League and made a promotion in the Serbian SuperLiga.[13][14]
During the 2014–15 Serbian SuperLiga campaign, Gašić was mostly sitting on the bench. He made his first appearance in the season in a cup match against Čukarički, played on 24 September 2014.[15] In the mid-season, Gašić suffered an ankle joint injury, after which he missed a period.[16] He made his Serbian SuperLiga debut for Mladost in 28 fixture match against OFK Beograd, played on 13 May 2015, when he replaced Nebojša Gavrić at 73 minute.[17] 5 minutes later, he made penalty for opponent team, and got the yellow card after one start on Ivica Jovanović at the penalty box.[18] He played all 90 minutes in 29 fixture match, in win against Radnički Niš,[19] and also had a solid role against Red Star Belgrade in the last fixture of SuperLiga.[20] After the end of season, Gašić left the club.
Napredak Kruševac
Gašić had signed with OFK Beograd in summer 2015,[21] but he changed his mind in short time, so he returned in his home town and joined Napredak Kruševac.[22] He made one-year deal with Napredak.[23] During the first half of 2015–16 season, Gašić was in protocol once time, for the 2nd Serbian First League fixture.[24] In the winter break off-season he was with team in Antalya, where played some friendly matches, but later he left the club.[25] For the spring half of 2015–16 season, Gašić was loaned to Serbian League East side Temnić,[12] where he stayed until the end of contract with Napredak.[26]
Borac Čačak
In summer 2016, Gašić moved to Borac Čačak, training with club and playing several friendly matches during the pre-season.[27][28] After many injuries in defence line, Gašić signed a contract with club at the beginning of August 2016, and made his debut for new club in 3rd fixture match of the 2016–17 Serbian SuperLiga season, against Voždovac.[29] In last days of the summer transfer window 2016, Gašić moved to Serbian First League side Kolubara on a six-month loan deal, where he failed to make a single league appearance.[30]
Trayal
At the beginning of 2017, Gašić returned to Trayal, training with the club until the end of West Zone campaign.[31] As he already appeared with 2 different clubs during the same season, he failed to play any official matches due to propositions. After the club captain Goran Rakić retired from playing football in summer 2017,[32] Gašić started the 2017–18 season in the Serbian League East with an armband.[33] He had been directly sent off in last minute of the home match against Jedinstvo Paraćin in 10th fixture of the campaign, which was his first red card as a senior.[34] Returning to the squad, he scored the first goal in the career on 11 November 2017, from direct free kick, being nominated for a man of the match against Prva Petoletka.[35] He was elected for the best on the field in the next fixture match, scoring a twice in 2–1 victory over Sinđelić Niš,[36] after which he was also awarded as the player of the week in the Serbian League East by Sportski žurnal.[37] Beside the captain's role, Gašić has also performed as a director of football in the club.[38] After beating FK Jastrebac from Veliki Šiljegovac in final match of the Kruševac City Cup on 19 April 2018, Gašić won his first trophy as a captain of FK Trayal.[39] On 26 April 2018, Gašić scored 4 goals including two realised penalty kicks in 11–0 victory over Juhor Obrež in semifinal match of the Rasina District Cup.[40] Beating Župa, Gašić also won a Rasina District Cup trophy with the club on 9 May 2018.[41] Several days later, Gašić scored in 1–1 away draw to Jedinstvo Paraćin.[42] Later, for the rest of season, Gašić also realised 2 penalty kicks in matches against Ozren Sokobanja[43] and Car Konstantin.[44] Winning the first place in the Serbian League East, Gašić made a promotion to the Serbian First League for the 2018–19 campaign.[45]
Gašić has been known followed by media since was announced he joined Red Star Belgrade on trial. After publishing an information he is a middle son of former Serbian Minister of DefenceBratislav Gašić, club's fans send a message against his signing.[53] Moving to Mladost Lučani, he became a target of speculation about the involvement of politics in his career again.[54] Gašić personally described his father many times as his idol and great support in life.[55] Milan has two brothers, Vladan and Nikola, who also involved in football.[56] Outside of the football, Gašić owns a gym, for which said he had built it without anyone's help.[57]
^Appearance in final game of the Rasina District Cup against Trayal[26]
^Including final round of the Kruševac City Cup against Jastrebac,[39] semifinal match of the Rasina District Cup against Juhor,[40] and final game against Župa[41]
^Including semi-final match of the Southern and Eastern Serbia Cup, against Zaplanjac,[46] and final game, against Moravac Mrštane[47]
^ ab"Trajal pobedom u novu sezonu". fudbal.info (in Serbian). 5 August 2018. Archived from the original on 10 August 2018. Retrieved 10 August 2018.{{cite web}}: CS1 maint: unfit URL (link)