Manchester United forward Marcus Rashford is set to start Saturday’s Premier League match against Southampton but team mate Anthony Martial has not yet recovered from a groin injury, manager Ole Gunnar Solskjaer said on Friday.Rashford was injured in last weekend’s 0-0 draw with Liverpool but played the full 90 minutes as United had used up all three substitutions.The 21-year-old, who has nine league goals this season, did not start in Wednesday’s 3-1 win at Crystal Palace but came on as a second half substitute.“He (Rashford) still felt it Wednesday night but he’ll be ready, I’ll probably start him,” Solskjaer told reporters.“You do have a plan but then you get suspensions, injuries. That one injury or one suspension might change the whole dynamic. It’s a matter of seeing who’s available now.”Martial has not played since he was withdrawn at half time in United’s 2-0 defeat by Paris St Germain in the Champions League last-16 two weeks ago.“It’s the last session today but we’re not going take any risks. Maybe Anthony, but it might just be a few more days before he’s ready, so probably the squad will look similar to what it did on Wednesday,” Solskjaer added.Solskjaer hoped goalkeeper David De Gea would sign a contract extension beyond 2020, reminding him of the trust the club and former manager Alex Ferguson placed in the Spaniard when he joined from Atletico Madrid in 2011.“Hopefully they will agree because David is the best goalkeeper in the world,” Solskjaer said.“The club showed how much they wanted him back in the day when (goalkeeping coach) Eric (Steele) and the gaffer found him.“There were probably better keepers there at that time. But the belief the manager showed in him, given the criticism he got, paid dividends.”Solskjaer was uncertain if Antonio Valencia, who is currently sidelined with a calf injury, would get a contract extension with the 33-year-old’s deal set to expire this season.“Antonio is still not 100 percent fit. At the moment I’m not sure if United and Antonio will agree on the next year. Hopefully I can get him on the pitch and he can show what he can do,” Solskjaer added.