Rafael Nadal
Rafael Nadal received treatment on a muscle injury at the top of his leg before retiring against Marin Cilic SAEED KHAN/AFP/Getty Images

Rafael Nadal is set to undergo an MRI scan on a leg issue that forced him to retire early from his Australian Open quarter-final tie against Marin Cilic on Tuesday (23 January) and revealed concern over the sheer number of injuries currently being suffered by players on tour.

The world number one, who would have faced Great Britain's Kyle Edmund in the semis and was on course for a potential final rematch with old rival Roger Federer, trailed 3-6 6-3 6-7 (5-7) 6-2 2-0 in an engrossing last-eight contest against the 2014 US Open winner on Rod Laver Arena when he was forced to call it quits due to a problem sustained while playing a dropshot in the fourth set.

Only once before in his illustrious career had Nadal been forced to retire from a Grand Slam match - the 2010 Australian Open quarter-final against Andy Murray - and he insisted afterwards that it was too soon to tell how it might adversely affect his plans for the rest of 2018.

"I can't say because I don't know," he said in a post-match press conference. "[It] just happened 10 minutes ago and [it] is impossible to know. We need to wait a couple of hours. Tomorrow I am going to do a test, an MRI here, then we will know. But now..."

Nadal, who withdrew from the ATP Finals last November with a lingering knee complaint, intimated that the injury was "high on the leg" rather than to his hip and said he would provide an update after a scan that is scheduled for tomorrow afternoon.

The Mallorcan's newest setback is the latest in a series of injuries to big-name players over the last 12 months and he encouraged tour organisers to consider the situation - particularly the firmness of the surfaces for hard-court tournaments, which he thinks could cause issues post-retirement.

"No, no, there is no reason [why he has suffered more injuries at the Australian Open than anywhere else]. But [it] happened. That's it," he added.

"[It] is not the right moment to say for me. Somebody who is running the tour should think [a] little bit about what's going on. Too many people [are] getting injured. I don't know if they have to think a little bit about the health of the players.

"Not for now that we are playing, but there is life after tennis. I don't know if we keep playing [on these] very, very hard surfaces what's going to happen in the future with our lives."

Elsewhere on day nine in Melbourne, Edmund became only the sixth British male singles player of the Open Era to reach the semi-final of a Grand Slam as he stunned third seed Grigor Dimitrov in four sets 6-4 3-6 6-3 6-4. The South African-born right-hander will replace the injured Murray as British number one if he reaches Sunday's final.

Women's number four Elina Svitolina suffered a shock heavy loss to Elise Mertens, who will meet Caroline Wozniacki in the last four.

The Dane overcame Carlos Suarez Navarro 6-0 6-7 6-2 in the early hours to reach the semi-finals in Melbourne for just the second time.