Pakistan bowler Usman Tariq and his unusual delivery courts controversy at T20 World Cup

With a momentary pause in his delivery and his statue-like pose at the crease, Pakistan spin bowler Usman Tariq has created plenty of attention at cricket's Twenty20 World Cup.

Just enough, it seems, to throw off opposing batters.

With it has come a fair share of controversy - that his pause and sling style of bowling is an illegal delivery, or in cricket parlance, chucking. He's already been reported twice, but cleared, by Pakistani cricket authorities.

The 28-year-old off spinner’s unconventional bowling action has already mesmerised some of the big names in shortest format of the game and has seen him taking three wickets against an inexperienced United States in Sri Lanka this week in what was his first T20 World Cup game.

As is often the case in cricket, the reasons for Tariq's potential illegal delivery are complicated.

First, there is the so-called "15-degree debate" - that bowlers cannot exceed the ICC's 15-degree elbow flex limit, which is nearly impossible for on-field umpires to judge accurately in real time.

Another talking point has been the pause in Tariq's delivery stride.

Baffling the batters

Batters like Cameron Green of Australia and South African Dewald Brevis are a few notable players that were flummoxed by Tariq's bowling action.

Power-hitter Brevis fell to Tariq's only second ball in T20 international cricket in November. Green shook his head in disbelief and mocked Tariq's bowling action close to the boundary line - but later apologised - when he walked back after slicing a wide delivery straight to the cover fielder during Pakistan's 3-0 sweep of Australia at Lahore.

Tariq's rise in T20 cricket has also seen him taking a hat-trick at Rawalpindi when he took 4-18 against Zimbabwe during the tri-series in November. He has taken 11 wickets off his 88 balls in only four T20 internationals.

It was no surprise when selectors included Tariq in the 15-man T20 World Cup squad, knowing that pitches in Sri Lanka would suit slow bowlers more than pacemen.

Tariq's journey to top-level cricket wasn't a smooth one. He was twice reported for suspect bowling action during country's premier domestic T20 tournament - the Pakistan Super League - over the last two seasons, but on both occasions he was cleared after testing at the National Cricket Academy in Lahore.

"I have two elbows in my arm," Tariq said.

"My arm bends naturally. I have got this tested and cleared. Everyone feels I bend my arm and all that. My bent arm is a biological issue."     Tariq has also featured in the Caribbean Premier League and with his deceptive bowling action he was the tournament's second-highest wicket taker for champions Trinbago Knight Riders.

Long pause a problem

"The batters are struggling to read Tariq because of the long pause the moment he steps on the bowling crease," former Pakistan captain Sarfaraz Ahmed, who has played with Tariq in the PSL's Quetta Gladiators, told The Associated Press.

"The long pause disturbs all the concentration of batters and when he bowls a fastish (delivery, after a long pause), or even a slow ball, it leaves the batters clueless."