Career
He plays mostly as a left-back, but is often used further up the pitch as a winger. He is known for his powerful shooting, as he often takes free kicks and penalties for his club Levadia In 2003, at the age of 18, Kruglov started his professional career with Levadia.
At the age of 21, after three seasons in Levadia, Kruglov moved abroad.
Lokomotiv Moscow On 8 June 2005, he signed a 5-year contract with Russian Premier League club Lokomotiv Moscow. He played his first Russian Premier League match on 3 July 2005, in a 4–0 victory over Terek Grozny.
But soon he fell out of favour at his new club and spent the second part of the 2006 season on loan at Russian First Division club Kuban Krasnodar, but failed to make a single league appearance for them. In mid-2007, he went out on loan again, this time to Torpedo Moscow.
He played there 14 league game.
Neftchi Baku On 29 February 2008, Kruglov signed for Neftchi Baku on a three-month loan from Lokomotiv Moscow. He played there 10 league game and scored 2 goals. Inter Baku On July 2010 he moved to Inter Baku.
The contract was not renewed at the end of 2010-2011 season.
Rostov On August 2011, Kruglov signed three-year deal with Russian Premier League side Rostov. He scored his first goal on 18 September 2011, against CSKA Moscow Ravan Baku Kruglov returned to Azerbaijan in March 2014, signing a contract with Ravan Baku.
On 20 April 2014, in a game against Gabala, Kruglov fell and injured his shoulder, resulting in a shoulder operation that ended his season and time with Ravan. Foreign Estonia national football team, Kruglov is capped 91 times, scoring 3 goals.
He made his national team debut on 12 October 2004 against Latvia in a World Cup 2006 qualification.
He scored his first national team goal on 12 November 2005, in a 2–2 draw against Finland in a friendly match from a penalty kick. In 2011, he was the only national team player who appeared in all 13 matches (12 in the starting eleven). International goals Levadia Meistriliiga: 2004, 2013, 2014 Estonian Cup: 2003-2004, 2004-2005 Lokomotiv Moscow Russian Supercup: 2005 Individual.