Portsmouth manager Paul Hart is confident Mike Williamson can make the step-up to the Premier League after landing the defender from Watford.
Pompey will pay an initial £2million, rising to £3million after various add ons, for the 25-year-old who the Hornets bought from Wycombe for just £150,000 in January.
Hart has also signed Tal Ben-Haim from Manchester City but expects Williamson to challenge for a first-team place.
"We've watched him play and he's shown great promise which hopefully he will build on under our guidance," Hart told Pompey's official website.
"We were a centre-half short before Sylvain Distin left but now we have Tal Ben-Haim and Mike Williamson.
"We signed Ben-Haim to fill a role and Mike has come here to prove himself as a front-line player."
Source: Eurosport