Charlie Wyke has upped his game since returning to the Sunderland side - and Phil Parkinson has challenged the striker to improve his form still further.

Wyke started alongside Chris Maguire against Carlisle in the EFL Trophy at the beginning of the month and contibuted a goal and an assist in the 5-3 win, and he followed up that performance with another goal in the league win at Swindon Town last weekend, and then another impressive display in the midweek win against Crewe.

Parkinson says Wyke has increased his 'physical output' in recent weeks, and that has been reflected in his willingness to close players down high up the pitch to enable the Black Cats to play the kind of high pressing game his manager wants to see.

And while Parkinson is happy with the way Wyke is playing, he says the fact that Will Grigg, Danny Graham, and Aiden O'Brien are all waiting in the wings is keeping him on his toes.

"I thought Charlie and Chris were excellent in the Carlisle game and they backed that up at Swindon," said Parkinson.

"I was pleased with their contribution the other night [against Crewe] but we have also got other players who are champing at the bit and who are ready and waiting.

"It's good to have those options and I feel that the clubs with the strongest squads will be successful this season because of the volume of games.

"We have to make sure that every player knows their role and their responsibility within the team framework, and what is expected of them.

"The last two games, Charlie has been good.

"People on the outside don't have the benefit of seeing what we see in terms of players' physical output.

"We want to be a team that presses from the front and Charlie has the capabilities to be outstanding at that - he is very fit and athletic, and he needs to show it on a regular basis.

"In the last two games we have got him back to where we want him to be, whereas earlier in the season the output wasn't quite where it needed to be.

"He's put that right and he has got his rewards, but the onus is on him to keep going if he is selected."

There was a question mark over Grigg's future at Sunderland this summer, and Gillingham boss Steve Evans claimed this week that MK Dons were interested in signing the striker.

But Grigg, who has struggled since joining the Black Cats in January 2019, stayed on Wearside and Parkinson has said the 29-year-old came back for pre-season in excellent shape and will play a part this season.

"Competition has to drive you on," said Parkinson. "You can't fear it.

"If a player comes in, you have to use that to push you onto another level and that's what Charlie has to do.

"In terms of Griggy, I stand by what I said - he's in terrific shape and he started the season well and was unlucky not to get a goal, but there will be a time when he is back in the team and he will have a big part to play."

Parkinson has chopped and changed his attacking players this season, with Grigg starting the season in the side, sometimes he has opted to pair summer signings Graham and O'Brien, while more recently Wyke and Maguire have played.

And while Wyke and Maguire have the edge as the men in form, Parkinson says he will continue to pick his teams based on a range of factors.

He said: "I just weigh everything up and pick each team for the game in hand, and form is one of the things that comes into that along with freshness, any little niggles, the opposition, etc.

"Everything factors into what we decide for the starting XI."