Sox second baseman Dustin Pedroia prepares to throw to first after fielding a grounder by the Cardinals’ Ryan Ludwick in the sixth inning yesterday.

The Providence Journal / Bob Breidenbach

BOSTON — When the Sox selected Florida high schooler Casey Kelly in the first round earlier this month in the First Year Player Draft and Portsmouth’s Ryan Westmoreland in the fifth round, they knew they wouldn’t be easy to sign.

Some 2½ weeks after the draft, that feeling hasn’t changed.

Talks are ongoing with both players. Kelly, a standout high school shortstop, has a football scholarship offer from the University of Tennessee.

Ordinarily, a “slot” salary — the figure Major League Baseball recommends to its clubs — for the final player taken in the first round is somewhere around $1.2 million, but Kelly’s contractual demands are thought to be nearly triple that amount.

Kelly has some leverage and the window for the Red Sox to negotiate isn’t as long as some other players heading to college.

Football practice begins for the Volunteers in late July, several weeks before the deadline to sign college-bound players. Once Kelly participates in football practice at Tennessee, he would be ineligible to sign with the Sox.

As for Westmoreland, an outfielder who has a baseball scholarship waiting for him at Vanderbilt, his signing bonus asking price — said to be well into the seven-figure area — is also higher than normal for his place in the draft.

The Sox continue to have discussions with Westmoreland’s adviser, but may not make much progress until the August deadline helps instill a sense of urgency to the talks.

Aardsma showing mound mastery

David Aardsma, who struck out the three batters he faced in the ninth inning Friday night, followed up with another strong inning yesterday, again striking out the side in the eighth.

That gives Aardsma six straight strikeouts in his last two outings. Moreover, over his last 10 appearances, covering 12 2/3 innings, he’s allowed only two runs on six hits while striking out 16. In that span, he’s compiled an ERA of 1.42. For the season, Aardsma’s ERA is 2.60.

Aardsma’s problem — both here and over his brief major-league career — has been command, but he’s been better of late, walking only five in the last 12 2/3 innings.

Still, the Sox don’t seem ready to have Aardsma move into a set-up role, preferring to use him for multiple innings early in games, or when they’re behind or comfortably ahead.

“His role has really helped us,” said manager Terry Francona, “and that’s a very important role. To change him I don’t think makes a lot of sense.”

Sore knee puts Timlin on DL

Red Sox reliever Mike Timlin has been placed on the disabled list with tendinitis of the left knee.

Taking his spot on the roster was Daisuke Matsuzaka. It had been thought that the Sox would return Chris Smith to Pawtucket to make room for Matsuzaka. Instead, Smith will stay — at least for a while — and Timlin will make his second trip to the DL this season.

“It’s something he’s been pitching through,” said Francona. “I think it has something to do with the inconsistency.”

Timlin is 3-3 with a 7.06 ERA and has given up 29 hits in 20 1/3 innings.

“We all ended up agreeing that this is probably the best thing for him and the organization,” said Francona.

The manager said the Sox will have Timlin rest for the remainder of the homestand, then probably be sent to Pawtucket to begin a rehab program.

“He’ll go out, try to pitch effectively and we’ll see how that goes,” said Francona.

A 42-year-old and 18-year veteran, Timlin was not in a good mood yesterday morning, saying the knee has been bothering him for a while.

“Enough to go on the DL,” responded Timlin. “It hurts sometimes and sometimes it doesn’t. It’s been around a while. It started to get bad enough to where I needed to pay attention to it, so we’ve decided to do this.”

Timlin said he’s never experienced this type of injury before.

Francona said he and the medical staff spoke at length with the veteran reliever after Friday night’s game.

“The good news is he doesn’t look like he’s hurting,” said Francona. “But there have been a lot of inconsistencies with his pitching.”

Manny to remain as Sox’ DH

Manny Ramirez, still hampered by a hamstring pull, will be restricted to DH duty for the rest of the homestand. The Sox are hopeful that the time out of the field will help him heal so that he can play left field again when the Sox begin an interleague road series Friday in Houston. With Ramirez as the DH, Brandon Moss started in left field yesterday.

Ramirez has been hampered with the discomfort for a while now, and Francona said he doesn’t see it going away anytime soon. Still, the slugger has been able to play through it and hasn’t shown any ill effects on the base paths.

“If he came to me and said ‘I’m dying to play left field’ then we would do that,” said Francona. “Until then, we’ll stay where we’re at.”

Moss wasn’t the only bench player penciled into the lineup yesterday. Alex Cora started at shortstop after Julio Lugo made two errors Friday night to up his total to 16 this season, which is more than double that of any other American League shortstop.

jmcdonal@projo.com