BERLIN (Reuters) - Martin Schulz, the European Parliament president who is returning to German politics, does not expect to run as the Social Democrats’ (SPD) candidate for chancellor next year, Der Spiegel magazine reported on Friday.

European Parliament President Martin Schulz holds a news conference during a EU Summit at the European Council headquarters in Brussels, Belgium December 15, 2016. REUTERS/Eric Vidal

Schulz’s decision not to run, if confirmed, would likely clear the way for SPD chairman Sigmar Gabriel to be the party’s candidate to challenge conservative Chancellor Angela Merkel’s bid for a fourth term in office next year.

Germany is due to hold parliamentary elections in September. Spiegel, without citing a source, said in its online edition that Schulz had indicated to close associates before Christmas that he no longer expected to be the SPD’s candidate for chancellor.

Schulz said in November he would not stand for re-election as speaker of the EU legislature and would instead campaign for a seat in Germany’s federal parliament next year.

He made no comment on suggestions he may succeed departing Foreign Minister Frank-Walter Steinmeier or become the SPD candidate to challenge Merkel for the chancellery.

However, many SPD members had hoped Schulz would run for chancellor, rather than the gaffe-prone Gabriel, who has been dubbed “Mr Zig Zag” by media for his policy reversals.

The SPD is junior partner in a grand coalition with Merkel’s conservatives.

A survey of 2,504 voters by pollster Forsa published on Dec. 28 put support for Merkel’s conservative bloc at 38 percent, with the SPD the second largest party on 20 percent.

Gabriel, 57, has a difficult job. As deputy chancellor in Merkel’s grand coalition, he has to show he is fit to lead the nation while also heading a centre-left party whose policies are often at odds with much of German public opinion.

In the last year, the anti-immigration Alternative for Germany (AfD) party has enjoyed a surge in support, siphoning voters away from the larger established parties. The Dec. 28 Forsa poll put support for the AfD at 12 percent.

German lawmakers from the Social Democrats, environmentalist Greens and leftist Linke party met earlier this month to explore the possibility of forming a coalition government to replace Merkel next year.

The meeting came after the same three parties joined forces in a so-called ‘Red-Red-Green’, or ‘R2G’, coalition in early December to take control of Berlin’s city government.

Divisions between the three parties at federal level - especially on foreign policy - have so far prevented them from forming a national government, even though they already have more seats in parliament than Merkel’s conservative bloc.