The Czech was loaned out to Sigma Olomouc, Vitesse Arnhem, FC Koln and Middlesbrough in recent seasons.
Chelsea defender Tomas Kalas heads back out on loan, this time to Championship outfit Fulham on a season-long deal.
The central defender or right-back had a similar spell with recently promoted Middlesbrough on an 18-month deal as he helped them to promotion to the Premier League last season, playing 30 times in all competitions. "The Czech defender, 23, spent last season with Middlesbrough and returns to the Championship with our west London neighbours", says a statement on Chelsea's official site.
I'm happy to sign because when you see the interest, it's one of the most important things.
"When I was at Middlesbrough nobody expected us in the playoffs, and after the two seasons Fulham have had, no one expects them to be that high".
The defender was not picked for the Czech Republic's Euro 2016 squad and has just three global caps under his belt since making his debut for the national team in 2012.
The 23-year-old seems to be a forgotten man at Stamford Bridge and has only made four appearances in his six-year-spell with the Blues.
The Czech Republic worldwide centre-back has spent the majority of the past two seasons on loan at Middlesbrough.