Avelino signed with the New York Yankees as an international free agent in 2011.[1] He made his professional debut in 2012 with the DSL Yankees, hitting .302/.398/.374/.772 with 1 home run and 25 RBIs. He split the 2013 season between the Gulf Coast Yankees and the Staten Island Yankees, combining to hit .303/.381/.399/.780 with 23 RBIs, and was an MILB Yankees organization All Star.[2]
He split the 2014 season between the GCL Yankees and the Charleston RiverDogs, hitting a combined .247/.308/.351/.659 with 2 home runs and 15 RBIs.[1] He split the 2015 season between Charleston and the Tampa Yankees, hitting .260/.314/.334/.648 with 4 home runs, 27 RBIs, and 54 stolen bases in 488 at bats.[1] His 2016 season was split between Tampa and the Trenton Thunder, combining to hit .260/.320/.364/.684 with 6 home runs and 48 RBIs.[1]
In 2019, Avelino played most of the season with Sacramento, with whom he batted .283/.315/.444 with 12 home runs, 17 stolen bases, and 62 RBIs in 473 at bats.[1] He also had seven at bats for the Giants.[7] He was designated for assignment on August 9, 2020. Avelino was released by the Giants organization on September 7.
Chicago Cubs
On November 20, 2020, Avelino signed a minor league contract with the Chicago Cubs organization where he was assigned to the Iowa Cubs.[1]
Los Angeles Dodgers
On June 8, 2022, Avelino signed a minor league contract with the Los Angeles Dodgers organization.[8] He played in Double-A with the Tulsa Drillers, appearing in 60 games and hitting .230/.288/.378 with seven home runs, 26 RBI, and nine stolen bases.[1] Avelino elected free agency following the season on November 10.[9]
On June 7, 2024, Avelino signed with the Staten Island FerryHawks of the Atlantic League of Professional Baseball. In 18 games for Staten Island, he hit .194/.267/.299 with two home runs, nine RBI, and three stolen bases. Avelino was released by the FerryHawks on July 1.[13]
Kansas City Monarchs
On July 20, 2024, Avelino signed with the Kansas City Monarchs of the American Association of Professional Baseball.[14] He went 2–for–3 (.333) with two RBI in three games for the Monarchs before he was released on July 29.[15] On August 7, Avelino re–signed with Kansas City.[16] After posting a .292/.333/.375 slash line with one home run and 11 RBI over 23 games, Avelino was released again on August 31.[17]