[4] Martins made his promotional debut on short notice, replacing an injured Justin Salas against Edson Barboza on 19 January 2013 at UFC on FX: Belfort vs.

[6] Martins faced Jeremy Larsen, a contestant of The Ultimate Fighter: Live, on 18 May 2013, at UFC on FX: Belfort vs. Rockhold.

[8] Martins next dropped from lightweight to bantamweight and faced promotional newcomer Junior Hernandez on 4 September 2013, at UFC Fight Night: Teixeira vs. Bader.

[12] Martins was expected to face Jim Alers in a featherweight bout on 16 July 2014, at UFC Fight Night 45.

[23] After racking a couple of wins in Brazil's regional circuit, Martins signed with Brave Combat Federation.

In the promotional debut Martins faced Fabian Galvan at Brave CF 3 and won the bout via Brabo choke in the second round.

[27] On 25 July 2019, Martins was defeated by Bubba Jenkins at Brave 24 by TKO at 2:48 of the first round by way of unanswered strikes.

However, the event has been postponed until a to-be-determined date due to the COVID-19 pandemic[29] Martins was next expected to face Luan Santiago in a rematch at Brave CF 41 on 17 September 2020.

According to BRAVE CF officials, Grabinski was forced to withdraw from the rescheduled bout a little bit less than week prior to the event due to Covid-19 protocols.

[35] Martins would then go on to face Henrique Marques on July 30, 2022 at Brave CF 60, winning via TKO stoppage a minute into the bout.

[36] Martins faced Ylies Djiroun on September 7, 2023 at Brave CF 74, knocking out his opponent in the first round.