MUMBAI, April 22 -- Both Chennai Super Kings and Mumbai Indians received a boost ahead of their IPL clash on Thursday with MS Dhoni showing signs of returning to full fitness during a high intensity training session and England's T20 World Cup star, Will Jacks, joining the hosts for his first training session. Dhoni has missed all six CSK games due to a calf strain. Ayush Mhatre's hamstring injury has been a body blow for CSK. Dhoni's return will be well-timed, lifting their morale after a frustrating 10-run defeat against Sunrisers Hyderabad. The 44-year-old trained hard, keeping wicket and batting for a long time. Coming off a dominating win over Gujarat Titans, MI will be further bolstered by Jack's availability. The spin-allrounder had ...