The Philadelphia Phillies have made a mid-rotation starting pitcher their top trade deadline priority, according to a tweet by ESPN’s Buster Olney .

The two-time defending National League champions, who find themselves two and a half games back and in third place in the NL East division, will look to supplement a rotation that already includes the dominant Roy Halladay and a pair of strong left-handed hurlers, in the ageless Jamie Moyer and 2008 World Series MVP Cole Hamels.

In order to do so, general manager Ruben Amaro would do well to place a call to Chicago Cubs GM Jim Hendry. While Philadelphia is an eager buyer as the July 31 trade deadline looms, Chicago finds itself eight and a half games out in the NL Central, and will look to move some soon-to-be free agents.

Among those players is Cubs left-handed ace Ted Lilly, 34. who has posted an impressive WHIP of 1.14 in his three-plus seasons on the North Side.

Lilly will become a free agent after 2010, at the close of a four-year, $40-million contract that has seen him strike out 3.21 batters for each one he has walked. Despite off-season shoulder surgery that sidelined him until late April and poor run support that has allowed him to win just twice in eight decisions this year, Lilly remains an effective starter.

Whether because his shoulder ailment yet lingers or because he simply hasn’t yet rebuilt full strength, Lilly’s velocity is down this year. That has mitigated his numbers somewhat, including key indicators like swinging strike percentage (7.6, down from 9.6 in 2009).

Still, Lilly has stellar command and occasionally dominant stuff. Just two weeks ago, White Sox pinch-hitter Juan Pierre broke up a no-hit bid for the southpaw in the ninth inning. Moreover, under the tutelage of fellow finesse lefty and fly-ball specialist Jamie Moyer, Lilly could discover even more magic.

A rotation featuring Lilly, Hamels and Moyer would admittedly be a bit more left-handed than is strictly optimal, and the looming return of left-handed J.A. Happ could make it dangerously so. Presumably, however, the Phils could reinstate Happ as a reliever, where he first pitched in 2009 before emerging as Rookie of the Year runner-up in the senior circuit.

On the Cubs side, trading Lilly makes sense even if they must eat some of the money left on his deal. All of that will be paid out by the end of October, and if the team can get a solid piece in return—24 year-old Double-A first baseman Matthew Rizzotti would make a good target—then it will have been worth parting ways with the man who has done more to make the team competitive during the past half-decade than perhaps any other.

The deal is an unlikely one, but both teams could sell it to their fans with relative ease, and it could provide Charlie Manuel with the extra pitching option he needs to guide his squad to a fourth straight division title.

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