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England coach Trevor Bayliss says Test places will be on the line at the start of the county season.
Bayliss has just overseen a second major series win in six months, beating South Africa 2-1 away from home to go with last summer's Ashes success, but question marks remain over key positions following a familiar blowout in the final Test.
Three of the top five - Alex Hales, Nick Compton and James Taylor - endured modest returns against the Proteas and face a nervous wait to see if they will be retained.
Jonny Bairstow did prove himself with the bat but proved an error-prone wicket-keeper and may not have long to prove he can combine both roles.
That means the beginning of the domestic season will be played for unusually high stakes, with the men in position vying with young hopefuls and more experienced heads, including Ian Bell, for the selectors' attention.
"We're by no means the finished article. There is some very good talent in the team, but there are a few rough edges to knock off as well and that will take some time," said Bayliss.
"I think that is a sign to everyone else in county cricket that, if I come out and score runs early in the season, there are possibilities there.
"There are four or five (rounds of) matches before that First Test against Sri Lanka. Those matches will be very important for some of those players.
"From a keeping point of view, Jonny is working hard and trying to get the right advice, but he is work in progress. Again, it is a message for any keepers out there that there may be opportunities down the line."
The most vexed of all positions is the second opening slot alongside captain Alastair Cook.
Hales is the eighth person to be tried in the role since Andrew Strauss' retirement in 2012 and an average of 17 in four Tests hardly precludes the possibility of a ninth.
Bayliss did see some signs of encouragement from the 27-year-old, who will stay on as a key part of the one-day squad in South Africa.
"He's one of the guys who would obviously be disappointed how he's gone in this series," conceded Bayliss.
"I thought the first couple of games, even though he didn't score a lot of runs in Durban, he looked quite comfortable at the crease and he looked like he belonged.
"He's one of those guys who has shown what he can do at this level...whether it is as an opener or somewhere else in the order, he is certainly a guy with a lot of talent."