I think it is the case of bogus news. It used to be Debka that generated these type of stories.
This has come up before and quite recently. I expect that there will be a similar press release?
From 4th August 2015.
Russia not planning to send troops to fight ISIS in Syria – Putin’s spokesman
The participation of the Russian military alongside the US in the fight against Islamic State militants in Syria, is not on the agenda, said Dmitry Peskov, the presidential press-secretary.
“No, this isn’t being discussed in any way. This issue isn’t on the agenda,” Peskov told reporters on Tuesday when asked about the possibility of Russian military involvement in Syria.
The press-secretary also told the media that Syrian President Bashar Assad, had never asked his Russian counterpart, Vladimir Putin, to send troops to battle IS (formerly ISIS/ISIL).
https://www.rt.com/news/311583-russi...ps-syria-isis/