Russia has been vague about exactly how many troops it has sent to Syria. Best estimates are at least 3,000 with troops being rotated back to Russia after a few month. The Russian effort it being touted by state controlled media as a rare victory for Russian troops. It was also revealed that the government had ordered 10,000 campaign medals for troops who participated in Syrian operations. These only cost about $30 each to make but are a big deal in Russia and among the troops because they mark the soldier as the veteran of a victorious campaign. This is important because it was not easy getting soldiers willing to go.
Initially being sent to Syria was not popular among the troops. Worse there was not a lot of popular support at home for Russians fighting and dying in Syria. In fact getting troops to go to Syria at all has involved using only true volunteers and paying large cash bonuses. This means pay of up to $4,000 a month for those at risk of combat, like special operations personnel and any troops who will be close to the front lines.
Russia learned the hard way in Ukraine that even among their most ardent nationalists there were few men willing to fight. Back in Russia the eager fighters are few in number and many are still needed in Ukraine (to keep the Ukrainian “rebels” in Donbas going) and the Caucasus (to keep pressure on Islamic terrorists down there). Russia is also increasing pro-war propaganda. But it has already found in Ukraine and Caucasus that this sort of encouragement has little impact the closer you get to the combat zone and none at all when you start shipping bodies back to families. So Russia is keeping troop levels (and friendly casualties) low in Syria and cash inducements as high as they need to be.
The mid-March announcement that Russian forces were being withdrawn from Syria really meant that the expensive and overworked combat aircraft were being pulled out (mainly to save money and because Russia does not have many of these new models) and to keep most Russian troops in Syria away from combat. Such concern for the welfare of the troops is unusual for Russia, but a century of wars, revolution, civil wars and communist misrule that killed off a quarter of the population had an enormous impact on Russians. Foreigners may not have noticed, but the current rulers of Russia have.