The top seed, who has been dealing with wrist pain since losing early at the Australian Open, made a trip to sub-zero Minnesota in January to have his specialist look at the problem.

So far, it's all clear for the Argentine who faces a huge test in the first round at the Ahoy stadium when he plays weekend Montpellier champion Gael Monfils of France.

After getting the medical OK to compete, 2009 US Open champion Del Potro, who competed in only a handful of 2010 event when his right wrist was hurt, remains cautiously optimistic of his chances of a trophy repeat.

He said his wrist is "improving day by day."

"Doctors are hopeful that my wrist will recover very fast. It is improving slowly, but at least it is improving.

"I'm trying to find a different treatment to fix the injury, to ensure that I can play the whole season."

Del Potro will highlight a Wednesday programme along with wild card entry Andy Murray, ranked sixth to Del Potro's fourth. Murray will open the Wednesday evening session against France's Edouard Roger-Vasselin.

The Argentine is playing as top seed for the tenth time in his career and has won five titles during his last five times at the top of the draw.

He has won seven of nine tournaments while standing atop the draw sheet.

The 25-year-old knows he is on shaky ground physically but remains relieved that doctors tell him his wrist can heal and that he can do it no more damage by playing.

For now, ranking dreams have to be tempered with reality.

"I'd like to remain in the top five and hopefully reach the top three. It will be difficult to pass (number one) Rafa (Nadal), (Novak) Djokovic and (Stanislas) Wawrinka, particularly after his recent Australian Open win.

"But I'm not the only one in the top 10 who has a lot of points to defend.

"I hope to do well in the grand slams and, at the end of the season, be close to the top three. Wawrinka took his chance and he got it. I want to again."

In opening-day play on Monday, qualifier Paul-Henri Mathieu, one of eight French players in the field, started with a victory over Croatian Ivan Dodig 4-6, 7-6 (7/2), 6-4.

The winner withstood 21 aces from his opponent to prevail in two and a quarter hours.

Number 140 Mathieu is playing Rotterdam for the fifth time, with his best a pair of second round showings.

The 32-year-old is making his second main draw appearance of the season after Montpellier last week.