Roger Federer accepts he is in a bit of an "unknown" physically heading into the Dubai Tennis Championships.
The Swiss great is set to make his first appearance since his Australian Open success when he faces Frenchman Benoit Paire in the first round on Monday.
Federer, the world number 10, battled a groin injury late in the year's first grand slam before claiming his 18th major.
The 35-year-old, a seven-time champion in Dubai, said he always expected to have some concerns heading into the ATP 500 event.
"Mentally I feel really fresh, physically I feel just fine because I was carrying an injury out of the Australian Open, the groin thing that I needed to have treatment on during the semis and finals," Federer said.
"I'm back in full training for only three days so it's still a bit of an unknown.
"But regardless if 100 per cent physically or not I was always going to feel a bit rocky coming into this event.
"It's still the beginning of my comeback plus conditions are fast, we'll see where it's going to take me but I'm excited to be here again after missing last year."