Ploskonossow started for the first time in November 2007 in Vershina Tjoi in the Eastern Europe Cup , where he finished 61st over 10 km freestyle and reached 15th place in the sprint. In November 2009 he achieved his first top 10 placements at the same location with eighth place in the sprint and over 15 km freestyle. A year later, Ploskonossow, again in Vershina Tjoi, achieved his first victory in the Eastern Europe Cup over 10 km freestyle. Ploskonosov made his first appearance in the cross-country skiing world cup in February 2013 in Sochi , where he came in 41st in the sprint. Subsequently, he achieved further results with seventh place over 10 km classic and fifth place in the sprint in Vershina Tjoi in November 2013 as well as seventh place in the 50 km freestyle mass start race and fourth place over 15 km classic in December 2013 in Krasnogorsk Top 10 in the Eastern Europe Cup. Also in December 2014 he placed in Krasnogorsk with fourth place over 15 km freestyle and tenth place over 30 km classic among the top ten. Ploskonosov had his next start in the World Cup in January 2015 in Rybinsk , where he reached the points for the first time with a 28th place in the 15 km freestyle and was 37th in the sprint.