Scally and Reyna have been close friends ever since they were trainees together at MLS side New York City FC, and both have made the step up to the Bundesliga in recent years.

Reyna moved to Dortmund in 2019, while Scally joined Gladbach in 2021.Sunday's clash could be the first time the two friends have played on opposing sides in the German league.

"We've been talking about it for a year now. Gio was at my house the other day and we're preparing to swap jerseys after the game," said Scally at a media roundtable on Thursday.

"He and I have been friends for about six years now. Both our families are visiting, and they're also very close," he added.

Scally and Reyna missed out on the opportunity to face each other when Gladbach and Dortmund last met in October, after Reyna picked up a hamstring injury which kept him sidelined for five months.

Reyna only returned in February, and has played one game since then after falling il last week.

"I felt terrible for him, it's really tough to be out for so long. But he's a great player and I'm sure he will bounce back," said Scally.

Dortmund are hoping to keep the heat on league leaders Bayern Munich with a win. They trimmed the Bavarians' lead at the top of the table to just six points last weekend.

Bayern, who followed last weekend's shock defeat to Bochum with another under-par performance against Salzburg in the Champions League in midweek, host bottom side Greuther Fuerth.

Bayern coach Julian Nagelsmann admitted after the Salzburg game that his side had communication problems in defence and "still had a bit to do to get level with Europe's elite".

They remain on course for a tenth successive Bundesliga title, however, and should maintain their six-point lead this weekend.

Bayern have not lost to Fuerth in the league since 1964, when both teams were in the second tier.

One to watch: Andreas Voglsammer

The Union Berlin striker is expected to return to the squad after missing last week's loss to Dortmund with Covid-19, and he would do so just in time to face former club Arminia Bielefeld on Saturday.

Voglsammer spent five years at Bielefeld before joining Union at the beginning of this season, and coach Urs Fischer said Friday that his history could provide "additional motivation".

Union need goals, having failed to score in both of their last two games.

Key stats

14 - Goals Bayer Leverkusen have scored in their last three games. A fourth four-goal haul in a row against Mainz on Friday would be a Bundesliga record.

3 - Defeats Bayern have suffered this season against teams from the lower half of the table.

Fixtures (all times 1430GMT unless stated)

Friday

Mainz v Bayer Leverkusen (1930)

Saturday

Wolfsburg v Hoffenheim, Stuttgart v Bochum, Augsburg v Freiburg, Arminia Bielefeld v Union Berlin, Cologne v Eintracht Frankfurt (1730)

Sunday

Bayern Munich v Greuther Fuerth, Borussia Dortmund v Borussia Moenchengladbach (1630), Hertha Berlin v RB Leipzig (1830)

Joe Scally

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