Cook steps into the breach while Vaughan fears another lost series

Michael Vaughan loitered around the periphery of England's first training session of the summer here yesterday. While his team-mates practised their cricket skills in the nets, the England captain frustratingly pushed out the miles on a Nordic cross-country ski machine positioned on the balcony of the indoor cricket school that overlooks the Nursery Ground.

What Vaughan was thinking as he raised a sweat, strengthened the muscles he hopes will protect his dodgy right knee and enviously looked on is anybody's guess, but last summer's Ashes success must now feel as though it was years rather than months ago. Vaughan will not play in the first Test against Sri Lanka which starts tomorrow and, after hearing that he is due to have another injection in the joint later this week, there is every chance he will miss the entire series.

Vaughan's absence looks set to give Alastair Cook, the young man who will replace him at No 3 in the order, three Test matches to confirm his undoubted potential. Cook knows that Vaughan will replace him once he is fit to play, but the Essex opener is determined to put the England selectors in a difficult position should this happen.

"Vaughany will obviously return when he is fit," Cook said. "But if you keep scoring runs they [the selectors] cannot leave you out." Runs are a commodity Cook has collected with ease in his short career. After a successful first season in county cricket he was selected to play for MCC - an unofficial England A side - against the Championship-winning county in April 2005, and he scored 120 and 97 in the match. Later that summer the 21-year-old struck a double century in a practice match against the touring Australians.

Yet his most impressive performance came in India this year when he was rushed into the England Test side. Cook scored 60 and an unbeaten 104 in Nagpur on his Test debut. His footwork was assured, and he looked unfazed by the challenges of Test cricket.

All these runs were scored while opening the batting yet Cook will bat at three tomorrow when he makes his home debut at Lord's. The prospect of batting out of position is not one that daunts the left-hander. "I used to bat at three for my club side, Maldon, when I was younger, and I have only batted there on a couple of occasions in one-day games for Essex, but you would bat anywhere for England. I do not see it as a problem. There is not much of a difference. The main difference is that you sit there with your feet up when the other two walk out to bat. It is still the same game and I will try and go through the same routines to make sure I am right when I go out to bat.

"Obviously I knew that Marcus Trescothick would open when he returned, and I initially thought that my only chance of playing was as an opener. But I am quite looking forward to batting at three. I am just glad to have been given another chance to stake a claim. My hundred at Nagpur has given me the inner belief that I can perform at this level. I know I am not going to score runs every time I go out, but scoring Test runs is not an unknown to me. Hopefully I can score a few runs and keep my place."

England's selectors will have had one eye on next winter's Ashes series when they announced that Cook would bat at No 3. With Vaughan's future uncertain, England want to find a possible replacement and give him as much practice as they can. Ian Bell fulfilled the role on three occasions in the winter but the selectors now feel that Cook has a game that can cope with the extra pace and bounce on Australian pitches.

Cook was not the only young cricketer to make a positive impression during England's winter tour of India: Monty Panesar will be hoping that the selectors show a similar attitude towards their spinner. Panesar is desperate to play but the figures at Lord's do not suggest that he will play a pivotal role in the game.

"I think every cricket side should contain a spinner because they normally come into play in the second innings of games," said Panesar. "But you have to take the conditions and the balance of the team into account as well."

The start tomorrow will be earliest ever for a Test match in England and, unsurprisingly, English spinners have made little impact. Ashley Giles is the only England slow bowler to take a Test wicket in May at the home of cricket, and these statistics may convince the selectors to play an extra batsman. The decision would disappoint Panesar but should he feel sorry for himself he need look no further than the Indoor School at Lord's. Vaughan would just love to be in contention.