A number of reports are now mentioning that Penn signed a deal worth 18M yen (through to the end of the current season) and was assigned the 44. Penn is expected to arrive in Japan on the 27th.
Penn's signing was a move to bolster the starting rotation.
The Chiba Lotte Marines have apparently signed Hayden Penn as news of him being added to the roster have just come through on the wire. No official announcements have been made as of yet.