According to spacenews.com NASA decided finally to seek alternative to planned manned Dragon and CST-100 spacecrafts with first regular missions scheduled for 2019. Explanation is simple - NASA resigned to purchase places for their astronauts for 2019 from Roscosmos, and in case of any delays with SpaceX manned Dragon or Boeing CST-100, 2019 could be first year without American astronauts inside International Space Station.
According to Bill Gerstenmaier, NASA associate administrator for human exploration and operations NASA would like to create alternative plan to provide continuous access to ISS in 2019 in case if SpaceX and Boeing would not manage to keep present schedule for their Dragon and CST-100 vehicles. It simply means, that NASA is not putting confidence in official schedule for Commercial Crew Program. To remind it covers first unmanned flight of Dragon in late 2017 with finishing certification in 2018 and first crewed mission in May 2018; alternative option, Boeing CST-100 should performed unmanned flight in May 2018. Both Companies are suffering for over 12 months of delay.
New plan, which should be announced in March, is based on two options. First is proposition of new edition of “year in space” program in the cooperation with Roscosmos; it could start in late 2018 and help in keeping one NASA astronaut for whole 2019. Another option is purchasing two seats inside Soyuz spacecrafts which were acquired by Boeing from RSC Energia as part of the settlement from 2015. It was result of a lawsuit between companies about Sea Launch joint venture, were both where business partners until 2011. Still both options are not comfortable for NASA and give only limited presence of NASA astronauts if we compare presented opportunities to present Expeditions with usually two NASA astronauts.