Langer, who has played in each of the biennial Ryder Cup matches since 1981, currently occupies eighth place in the standings, and victory in this weekend's tournament would almost guarantee his place at Brookline in September.
Rocca, a Ryder Cup member for the last three matches, has had a mediocre season and languishes in 30th spot in the points table, with only the top 10 certain to be in Mark James' side to face the Americans.
Many of the big names of the European game are concentrating on the build-up to next week's US Open, but Langer has failed to win an exemption for the event for the first time since 1985 and has a great chance of landing his first Tour victory for 18 months.
"I played well on the second day at Wentworth [where he finished tied seventh in the PGA Championship] which was good, but playing in Germany is more of a challenge," said Langer "As for the Ryder Cup, it's one of my goals to make the team again but we still have a long way to go. Every year we have some young guys coming in to join the experienced proven guys and it's proved to work well."
The Australian, Stephen Allan, will not defend the title he won last year after qualifying to play in the US Open, and Sweden's Per-Ulrik Johansson has also withdrawn after qualifying for the second Major of the year at Pinehurst.Reuse content