Samsung Electronics Co. is is losing a key mobile exec just weeks before the expected launch of its next flagship phone, the Galaxy S6. Kim Seok-pil has stepped down from his position as head of strategic marketing for Samsung’s mobile business after being appointed in December, the Wall Street Journal reported Tuesday.

Kim played an integral part in the development of the upcoming Galaxy S device, likely the Galaxy S6. However, his decision to step is not related to performance, but rather his ailing health. Kim could rejoin the company at a time point, the WSJ noted. However, several Samsung executives have been demoted or lost their jobs in recent months following the company’s abysmal 2014.

Replacing Kim is Samsung executive, Lee Sang-chul, who currently heads Samsung Mobile in Russia. Lee was previously head of Samsung Mobile in Latin America, and comes into his new position at a poignant time for Samsung. The smartphone maker struggled with drops in sales and profit throughout 2014, reporting a 64 percent drop in profit for its mobile business during its fourth-quarter earnings last week.

Samsung shipped between 71 million and 76 million smartphones during the fourth-quarter, a steep drop in comparison to the 85 million to 86 million units it sold the prior year. The manufacturer also saw rival Apple Inc. catch up to its global figures, selling 74.5 million iPhones during the fourth quarter. Samsung has been the largest smartphone manufacturer for some time; however, in the last year several rivals, including Apple, but in particular domestic makers like Xiaomi, Huawei and Lenovo have steadily eaten away at the company’s market share.  

Samsung is looking toward the Galaxy S6, which should launch on March 1 in Barcelona, to recover some of its lost sales. The manufacturer is expected to introduce updated designs and features on the phone, making it unlike any prior Galaxy S smartphone, to recapture lost customers. Samsung’s Galaxy S5 flagship especially suffered from sales losses, having sold 40 percent fewer handsets than the previous Galaxy S4 smartphone, which was a consumer favorite in 2013.