Don't ever accuse Michael Capellas of not enjoying a challenge. He worked alongside Carly Fiorina to push through the sticky sale of Compaq to Hewlett-Packard(NYSE: HPQ), and is now headed out of HP's doors to possibly take the helm at WorldCom.

Capellas has served as HP's president since the acquisition was completed in May of this year. He was Compaq's chief executive officer and chairman before that. A seasoned and well-respected executive with some 20-plus years of working in technology (including at Oracle(Nasdaq: ORCL) and SAP America), he joined Compaq in 1998 as its chief information officer.

His loss will be felt at HP. Fiorina won't replace his position and therefore will be responsible for the day-to-day operations Capellas handled so deftly. He was the man in the trenches, keeping the combined company on target. Can Fiorina do the same, as effectively? Investors don't seem sure, and shares of HP are trading down today about 9%.

According to The Wall Street Journal, Capellas is on the shortlist of candidates to head up bankrupt WorldCom. No comment from either HP or WorldCom today about the possibility, but if it were to happen, it would be a coup for WorldCom. Capellas is considered one of the ablest and brightest tech executives around; his leadership could make all the difference at a company many have written off altogether.

WorldCom is reportedly a few days to a week away from announcing its decision on its new chief. The court-appointed monitor must give the go-ahead for the CEO's compensation package, in addition to getting the green light from WorldCom's board, senior management, and creditors' committee.

There is still much to be done on the WorldCom side, and lots of uncertainty surrounding the entire situation. Will Capellas be named as WorldCom's new head? How will Fiorina and HP manage without him? Will he go on to do something completely different? Stay tuned.