One penalty save will not eradicate all of the doubts, but the sudden acclaim of Fraser Forster at the end of last Saturday's victory over Hearts seemed a reflection of his growing worth.

He was a goalkeeper in need of appreciation, at least from the broad extent of the Celtic support, and his reaction to securing the 1-0 win was a surge of emotion. Forster roared, as if liberated.

In his second season at Parkhead, and in the fifth loan spell of his career, he is seeking stability. There is a clause in the agreement between his parent club, Newcastle United, and Celtic that allows this current move to be made permanent for a £2m fee. Having had a £1.5m offer rejected last summer, and watched his development continue, Celtic might now consider that the price offers value for money.

At 23, there will still be moments of rashness from Forster, and he remains reluctant to use his broad 6ft 7in frame to dominate his area. Opposition strikers do not cower from him, but he is a capable shot stopper, as his penalty save from Eggert Jonsson last Saturday proved. There was also an act of devilment, since he protested at the positioning of the ball on the penalty spot, and so applied some extra psychological pressure to the Hearts midfielder.

This element of his game, a brash authority, continues to be mostly absent, though. Forster needs to be the dominant figure in Celtic's defence, imposing his command on the back four. When Neil Lennon was asked to identify the best goalkeeper he played alongside, he immediately responded, "Artur Boruc". The Pole was a compelling mix of arrogance, brawn, assurance and talent, who was also quick to lambast any team-mates who made a mistake in defence. "I like a goalkeeper to dominate his back four and take great delight in getting after them to keep them on their toes," Lennon explained.

Forster kept 24 clean sheets last season, a record, and four in his last five games. Yet he is not an imposing presence, even if physically he towers over players. The domineering attitude will come with age, and what best serves the goalkeeper in his formative years is a strong mentality. Despite a mix-up with Cha Du-Ri that led to Rennes scoring in France last October, Forster went on to make several impressive saves in the game. He will commit further errors as he develops and, particularly at a high-profile club such as Celtic, where success is measured in trophies won, he cannot succumb to any self-doubt.

"As long as it's the occasional mistake, but that's the case with Fraser," says Bryan Gunn, the former Aberdeen and Norwich City goalkeeper who watched Forster closely during his loan spell at Carrow Road. "Fraser's done very well at recovering and that's the attribute that all the top goalkeepers have. You get on to the next part of the game and wipe it away from your memory. At Norwich he was fantastic and some of the saves he made helped them win the league. When John Ruddy took over the following season, he found it difficult because Fraser had set such high standards."

With his height and the long reach of his limbs, Forster can seem ungainly. Following Celtic's 1-0 defeat to Atletico Madrid in the Europa League two weeks ago, the goalkeeper was described in the Spanish press as having "the grace of an elephant". The depiction was cruel, since Forster can move swiftly for such a tall figure, but there remains a separation between perceptions of him and his true potential.

After Forster's season-long loan at Norwich, Paul Lambert identified him as the best young goalkeeper he had seen in his career, claimed that he would be "world class" and could one day play for England. The plaudits were generous after a campaign in League One, but there is time enough for Forster to prove the observations authentic. The penalty save from Jonsson will renew his confidence, and Lennon already detected a more aggressive, formidable attitude in the goalkeeper's display at Celtic Park.

"It's a confidence position and the more times that you come off the pitch having kept a clean sheet and made important saves, receiving plaudits from sponsors and the press, the more confident you become," says Gunn. "That makes you play better and as a young goalkeeper, Fraser will be inspired on to bigger and better things. He's got the physical attributes, an excellent build, and maybe there's a bit of youthfulness there. He's still learning his trade. It's a great experience for him as a young goalkeeper, playing at a high level with Celtic. Fraser needs to decide now where his future lies. He's done very well in his time at Celtic and he'll need to think about his career and what his next move will be."

Forster wants his next move to be permanent, so that he can settle down and establish roots somewhere. If his preference might have been Newcastle, having grown up in Hexham as a supporter of the club, he has not played a single competitive first-team game during his six years at St James' Park. It is at Celtic that Forster is fulfilling his potential, and it would suit both the player and the club to extend their relationship.