2010-11: Nedeljkovic played for the Cleveland Barons bantam AAA team — posting a 1.97 goals against in 52 games. He was among the youth goalies invited to the 2011 Warren Strelow National Team Goaltending Camp run by USA Hockey.
2011-12: Nedljkovic appeared in two games with the Cleveland Barons U18 midget team and played goal for the Belle Tire U16 team that finished second in the Midwest and was third at the 2012 USA Hockey Tier 1 U16 Nationals. He had a 4.32 goals against and .889 save percentage with the Barons. Nedeljkovic had a 1.88 goals against and .903 save percentage in 18 regular season games for Belle Tire and posted a 2.50 goals against and .915 save percentage in four playoff games. He was selected by Plymouth in the sixth round (123rd overall) in the 2012 OHL Priority Draft.
2012-13: Nedeljkovic made his OHL debut with Plymouth as a 16-year-old — after spending time with the Metro Jets in the NA3HL — and gradually took over the starter’s role for the Whalers. He was 19-2-1 with 2 shutouts in 26 regular season games for Plymouth; posting a 2.28 goals against and .923 save percentage. The Whalers finished first in the West Division and reached the Western Conference finals against OHL champion London. Nedljkovic appeared in all 15 playoff games. He was 9-5 with 1 shutout and had a 2.71 goals against and .908 save percentage. In nine NA3HL games with the Jets he had a 2.49 goals against and .933 save percentage. Nedeljkovic attended USA Hockey’s Select 17 Festival in July, 2013.
2013-14: Nedeljkovic played for the USA U18 team in the 2013 Ivan Hlinka Memorial Tournament in August before returning to Plymouth for his second OHL season. He finished the year leading the USA U18 team to a gold medal at the World Juniors in Finland. In 61 regular season games for the Whalers he was 26-27-7 with 1 shutout and had a 2.88 goals against and .925 save percentage. Plymouth finished fourth in the West Division and faced eventual OHL champion Guelph in the first round. Nedeljkovic started all five playoff games and was 1-4 with a 4.41 goals against and .905 save percentage. In six games at the WJC he was 5-1 with 1 shutout and had a 1.84 goals against and .902 save percentage. Nedeljkovic was 3-1 in four games at the Ivan Hlinka Tournament, suffering his only loss in the gold medal game against Canada. He had a 2.99 goals-against and .897 save percentage. Nedeljkovic was named to Team Cherry for the 2014 CHL/NHL Top Prospects Game. Ranked fourth amongst North American goaltenders in the Central Scouting final rankings he was selected by Carolina in the second round (37th overall) in the 2014 NHL Draft.
Nedeljkovic was one of the top goalies in major junior hockey in his draft year. He combines his athleticism and never-quit style with exceptional focus, and he uses that to make up for any perceived lack of size he might have.
Nedeljkovic suffered a thumb injury during summer training that kept him from attending the Hurricanes development camp and the USA Hockey Evaluation Camp in Lake Placid. He participated in Carolina's training camp before being returned to Plymouth for his third OHL season in 2014-15. A workhorse for the Whalers, he appeared in 19 of 23 games to start the year. While he has not matched his goaltender of the year numbers from the previous season, that could be partly attributable to Plymouth as a team struggling with several new faces. Long-term his skill set and mental approach suggest he can be a dependable starter in the pro level in the future.