Squad rotation has gradually become an accepted part of modern football, with top teams generally possessing at least two good options in every position.
It helps managers keep players fresh, means they have an insurance policy in the event of injuries, and often allows them to make tactical choices for individual matches, without sacrificing quality.
For Arsenal, strength in depth has been particularly obvious at full-back this season, where five separate players have shared starting responsibilities roughly equally. While some would prefer consistent defensive unit like the famous back four of the 1990s, that’s less achievable in today’s game.
On the right, Arsenal have a trio of newcomers for 2014/15: Calum Chambers has started 13 league games at right-back, Hector Bellerin nine and Mathieu Debuchy eight.
On the left, there’s been something of a job-share arrangement between Kieran Gibbs, who has has made 16 league starts at left-back, with Nacho Monreal making 14.
More interesting than the simple appearance records, however, is the different balance it provides Arsenal from game to game. On the right, Debuchy’s double injury setback means he hasn’t been particularly prominent this season, although an hour in a midweek friendly match suggests he is nearing full fitness. In his absence, it’s been a selection between two youngsters, Chambers and Bellerin.
Chambers is another who has played in the centre of defence - and, in fact, central midfield away at Southampton on New Year’s Day - and that explains why type of full-back he is. He’s a solid, physically imposing footballer who many predict will eventually become a regular in a central position.
“At centre back, I feel more confident than at right back,” Chambers told the Arsenal matchday programme earlier in the season. “I feel like I read the game better, I feel more assured in myself.”
Wenger agrees. “He looks to have more qualities to play through the middle than through the flanks,” he said. “On the flanks you want explosive players.”
That, of course, is where Hector Bellerin comes in. An incredibly fast right-back who broke Theo Walcott’s 40-yard sprint record at the club, Bellerin is less dominant physically than Chambers, but more natural at speeding down the outside to make sudden overlapping runs.
Debuchy, meanwhile, is a combination of the two styles. Nine years older than the other two, Debuchy’s experience means he’s become a good all-rounder, and combines the two styles nicely, both covering for his centre-backs and attacking energetically. Arsenal fans might see his best form next season.
On the left, there’s a similar contrast. Gibbs’ defining qualities are his acceleration and his timing of overlapping runs, but Monreal has become a regular in recent weeks with his reliable defensive positioning and his more understated method of attacking.
He’s been particularly valuable in big away fixtures this year in the final third, winning a crucial penalty in the 2-0 league win over Manchester City, and opening the scoring in the 2-1 FA Cup victory against Manchester United.
Ideally, the two full-backs should offer a nice balance - one explosive overlapper, one more reserved, steadier player. Bellerin and Monreal have been the regular combination in recent weeks, and the two Spaniards offer precisely that.
In the 2-1 victory over Leicester in February, for example, the difference in their style was clear. Monreal was more involved in play, a key part of Arsenal’s passing build-up. Bellerin’s contributions were more sporadic, but when he got forward he attempted more crosses, and a shot on target.
However, the approach can be changed. For example, the 2-1 win away at QPR saw both Bellerin and Gibbs starting - and Arsenal’s best attacking moments came from the full-backs overlapping, with Gibbs storming forward to create the opener for Alexis Sanchez. The number of crosses was significantly higher, from both sides.
On the other hand, the recent 2-1 victory away at Newcastle saw more reserved full-back performances, because Chambers and Monreal started together. Therefore, Arsenal didn’t attack so energetically and depended upon set-pieces for the two goals, but they defended excellently throughout.
Three matches, three 2-1 victories, but three very different performances. Arsenal have shown they have quality at full-back - but, crucially, tactical variety too.