That is the reason we go! The reason we need to pray for those who go is also a commandment from Jesus himself.
Not only does he need more workers for the harvest but in many countries the harvest is gathered at great personal risk, it is dangerous to be a Christian in many places. Christians are dying for their faith still today. So every one sent into the mission field needs prayer cover. They need us to pray for their guidence and protection. They are rightly trusting in God and being obedient to the call that He has placed on their hearts but we need to uplift them in prayer for their protection and pray for a blessing on their work. Overseas missionaries have left their culture, home and comfort zone to share the gospel with those who need to hear it - and that's everyone! So pray even for the ones here in our country now from overseas.
Remember also that the mission field is right outside your front door wherever you live. Or in the cloud where you connect to the world and others. Be lights shining in the darkness and my prayers and blessings to you all.