Roger Federer
Roger Federer will skip the clay court swing for the second consecutive seson in 2018.Harry How/Getty Images

Roger Federer's decisions to pick and choose tournaments on the comeback from a knee injury has come under severe criticism from former French Open champion Ion Tiriac.

The 78-year-old, who hosts the annual ATP Masters 1000 tournament in Madrid, questioned Federer's approach, which he thinks would not be welcomed in any other sport. Despite maintaining that the 20-time Grand Slam champion is the best player ever, Tiriac expressed concerns about his behavior.

Federer has carefully planned his stops ever since he came back to the tour after suffering a six-month injury layoff in 2016. The 36-year-old has skipped the whole of clay court swing of the tour for two successive years — 2017 and 2018.

The Swiss legend had won the Australian Open crown, his 18th Grand Slam title last year and he went on to win the Sunshine Double before making the decision to skip action on the dirt, including the French Open.

The decision worked wonders as Federer was able to avoid injuries en route to his eighth Wimbledon crown.

Federer's decision to snub clay court season in 2018 seems to be a more reactive than proactive as he showed signs of a dip in intensity in Miami, following a tough defeat in a marathon final against Juan Martin del Potro at Indian Wells Masters.

"Roger Federer is certainly the best player ever, but he does not behave correctly. I do not think his approach is fair," Tiriac told Sport Bild.

He added: "Lewis Hamilton does not just say no more after five Grands Prix in Formula One because he does not feel like it."

Nadal returns to action in Valencia

Federer, who last featured in Miami Open last month, is expected to be back in action for his title defense at the Gerry Weber Open, ATP 500 tournament, starting June 18 in Halle. Notably, the tennis ace said he was hoping to go on a vacation and then give 100 percent on his comeback.

Meanwhile, Rafael Nadal, who has leapfrogged Federer to the top of ATP Rankings, is making a return to competitive action in Davis Cup World Group quarter-final tie between Spain and Germany, which will be played Valencia between April 6 and 8.

Nadal has not played since retiring from Australian Open 2018 quarter-final in January with a hip injury. Following the Davis Cup action, the 16-time Grand Slam winner will start his title defense at Monte-Carlo Masters from April 15.