General Grant reports that General Johnston gave his infamous "attack Sherman at Clinton" order to three riders, one of which was a Unionist spy who had been very publicly run out of town in Memphis in 1862.
However, General Johnston specifically states that he gives the message to Capt. Yerger, who said that he tried nearly all night to find Pemberton's HQ but, exhausted, decided to call it quits for the night and rent a room at a local inn. He claims that he handed the message off to a Pemberton staffer that was staying at the same inn ... and of course, the message ends up in McPherson's hands.
The same Capt. Yerger arrived in Raymond around 3 a.m. and took command of the squadron of Wirt Adams' men who were supposed to be patrolling the roads towards Utica and Port Gibson. Yerger ends up conveniently unengaged on the Port Gibson road all day, and Wirt Adams, who had been ordered to move with his entire force to Raymond, does not show up with his force of 800 men (plus nearly 500 men of the 20th Mississippi Mounted Infantry) until the Confederate force is in full retreat.
The bottom line is that Capt. Yerger ends up connected to McPherson during two of the campaign's most critical turning points: Raymond and Champion Hill.