HAWTHORN is awaiting scans to discover what caused forward Jon Patton to leave Thursday's fadeout loss to Essendon before quarter-time. 

In just his second match back from a long hamstring-related layoff, the 27-year-old former Giant pulled up short while preparing for a contest and left the field with a leg injury. 

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Hawks coach Alastair Clarkson said the club's doctors believed Patton had avoided an Achilles rupture, with a calf injury the more likely problem for Patton. 

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It is the third setback of his horror first season in brown and gold, after he spent the best part of the previous season-and-a-half recovering from a third knee reconstruction. 

Patton also missed time this season with a blister on one of his feet that became infected, and looks set to finish the year playing only six matches. 

"He's had a tough run, and that's quite often the case with guys who miss a lot of footy with one ailment, then they try and get themselves back and going again," Clarkson said 

"He worked really hard to get himself fit and ready to play … then played quite well last week against Port Adelaide and gave us a target up forward. 

"We're thinking, 'This is a good step in the right direction for him', but then nearly the first contest he went for tonight he hurt himself. 

"So we'll see where that goes and he'll be disappointed, but he's confronted setbacks like this before and he'll just have to do it again." 

Removing the Essendon clash and the round six match against Collingwood, Patton's still kicked only three goals in the other four games and had no more than seven disposals in any of them. 

Patton crossed from Greater Western Sydney in last year's Telstra AFL Trade Period on a three-season deal. 

Hawthorn was primed for a comfortable victory at half-time, when it held a six-goal lead – courtesy of 17 scoring shots to six – but had no answer to the Bombers' second-half onslaught. 

Essendon thrashed the Hawks 20-6 in the centre clearances, while winning the inside 50s 31-11 in the second half as Andrew McGrath, Zach Merrett and the returning Joe Daniher shone. 

"What was concerning for the whole game was the clearance rate," Clarkson said. 

"We were behind at half-time in that space and having to bounce from the back-end to try and give ourselves a chance – and we actually did that OK in the first half, but in the second half it just became a little bit overwhelming." 

Hawthorn rested captain Ben Stratton and super-veteran Shaun Burgoyne, on top of being without James Sicily, Jaeger O'Meara, Isaac Smith, James Frawley and Ricky Henderson. 

Clarkson said: "Our young guys just couldn't cope with the avalanche that came in the second half."

Meanwhile, Bombers coach John Worsfold was in a playful mood post-match, delighted with Daniher's spectacular return and how the side's game style flourished after half-time. 

Daniher finished with 10 marks and three goals from his first match in 467 days. 

"You just very quickly remember how good a player he is," Worsfold said. 

"My comment at my press conference yesterday was that it's good for Joe and it's good for us, but it's good for footy – and I think everyone will be happy to see Joey back out there playing footy and enjoying himself.

"He's been committed to getting himself back to this point. He's had setbacks, it's been frustrating and there's no question he would have had doubts at some points about what's going wrong here. 

"But all the way through he's been open to working with a team to get him back playing."