Brent Barclay takes the reins again after the 4yr-old began a new campaign at Ascot Park on Sunday.
Arden's Concord was last in an eight-horse field but picked up the bit well to run in to fifth.
But the concern this week is the gelding's first look at the barrier strands.
''It's just his first stand that we're not 100% sure what he's going to go away like,'' Barclay said.
''As long as he is walking in, he should be OK because he is a pretty nice pacer. They've got him on the unruly so he's back there by himself.
''If he's in with a couple of lengths of the leaders, he's got a bit of toe, so he could be a place chance.''
The Matt Saunders-trained pacer, part-owned by Westwood Beach trainer Graeme Anderson, may improve a length or two with the addition of pull-down blinds in the future, Barclay said.
''He's just not really finishing his races off, I don't think - he's got a bit more to offer,'' he said.
''Hopefully, they get the blinds on him. If it's not this start, it could be the next start and that might just spark him up a wee bit more.''
River Black has made plenty of trips to both Forbury Park and Southland, so it may be surprising to learn Barclay has never driven the 8yr-old in his 70-start career. However, he has driven against the Dean Taylor-trained pacer enough times to know his best racing pattern.
''He looks like he's one of those horses that has to be put in the race at some stage,'' he said.
''I haven't really been talking to Dean - he just left a message on my phone - but he will be a good drive, I will say.''
River Black has not raced since he had to pull a flat tyre in to ninth at Addington on July 24. This is a step up in grade from that assignment, but his form prior was hard to fault.
''He's been there and done it all before. He's not going as good as he was going a couple of years ago, but he's dropped back.''
River Black has won three times over the middle distances in his career, but Barclay will need to find an opportune time to press forward and pressure some of the runners inside such as Greenburn Creek and Heretic Franco.
Explosive Star is an even chance in a c0-c1 trot field which lacks depth. Two maidens are off the front line, and the Michael Heenan-trained 5yr-old is drawn on the inside of the c1 trotters 30m behind.
''I just watched its replay the other day and I thought its run was really good at Oamaru,'' Barclay said.
''Michael said he was happy enough with it. He said it's no star but it's probably as good as anything else in that field.''
Barclay does not expect much from Sundon Invasion in race 4, though.
''I watched the replay of that, too, and it didn't look focused at all.''
