If it weren't for the calf strain I'd say it would depend how important the XC result was for you.  Even then I'd say an all-out effort on Wednesday might be a bit much.  As it is, two very hard efforts in 5 days is nothing other than a foolish injury risk IMO.  Skip the time trial and only hammer the XC if the calf feels 100%.

Good evening Runners World,I'm asking for advice here - on club night on Wednesday I've got the opportunity to do a 5km time trial, but is pushing myself really hard a bit dangerous if I want to really put in a great performance at the upcoming Cross Country race on Sunday ? Would it be wise to put in some steady pace miles as opposed to going all guns out ?I'm sonly just back from a calf strain also, so I'm maybe overly cautious.I've put in around 7km tonight, and will put the same in on Thursday and gym Saturday morning.Would appreciate some advice. Cheers !