Jamie Roberts undergoes HIA after James Haskell's red-card tackle
Wales centre Jamie Roberts is undergoing Head Injury Assessment (HIA) protocols with Harlequins after being floored by Wasps' James Haskell.
England back-rower Haskell was sent off after his shoulder collided with Roberts' head in a tackle.
Roberts left the fray and Haskell later apologised for the incident in Quins' European Cup win over Haskell's Wasps.
He has three weeks to recover to be in contention for Wales' home Six Nations opener against Scotland on 3 February.
|What is a Head Injury Assessment|
|1. Player must correctly answer a series of simple questions including: What venue are we at? Which half is it?|
|2. Immediate memory test: Player must remember and repeat a sequence of five words|
|3. Player must remember sequences of numbers and repeat them in reverse|
|4. Balance evaluation: Player must walk by putting one foot directly behind the other|
|5. Symptom checklist: A doctor checks for symptoms including headache, nausea and blurred vision|
|6. Player is asked to remember words from immediate memory test (3)|
|7. Doctor checks for clinical signs like drowsiness and emotional distress|
Roberts replied on social media to Haskell's apology, tweeting: "Head's ok. Enjoyed that win with this resilient group of @Harlequins lads.
"Hope your shoulder is ok after colliding with this jaw @jameshaskell - Good man for apologizing ....just bend those arthritic knees next time pal ;)."
A Quins spokesperson said "all seemed well" with Roberts after the game, adding: "But he will have to follow HIA protocols, so [we] can't give an exact timetable on when he'll be back."
Facing Scotland would mark 10 years since Roberts made his Wales debut on the wing in their 30-15 win against Scotland on 9 February, 2008 on the way to a Grand Slam in Warren Gatland's debut season in charge.
The 31-year-old has won 94 Wales caps and three more for the British and Irish Lions.
But while the 2017 Lions were in New Zealand, Roberts led Wales to tour Test wins against Tonga and Samoa.
He was subsequently left out of Wales' initial squad for their autumn 2017 internationals, but recalled after injuries struck and came off the bench in their 33-18 defeat by New Zealand.